DENVER -- The manhunt for Brent Brents -- the suspect linked to six sexual assaults -- has intensified as Denver police take their search nationwide and the reward for his capture increases to $40,000.

Video

Hear Brent Brents Voice

On Friday morning, Denver Police Chief Gerry Whitman appeared on several national media outlets asking people across the country to help catch the registered sex offender.

Even though Brents' vehicle was impounded after it was found at a supermarket parking lot near his home, Denver police are not ruling out the possibility that Brents, 35, has already fled the state.

"We don't know if he left the state or not, but we're not taking any chances," Whitman said. "I think all the media attention has driven him underground and I think he may have left the state and there's no way to get that information in a (more) timely fashion than through the media."

There's now a $40,000 reward being offered for information leading to Brents' arrest. Tips picked up Thursday after police announced that an anonymous donor kicked in $18,000 for Brents' capture. Then on Friday, that reward grew to $40,000 thanks to more anonymous donors. Police did not know how many donors have kicked in the additional $20,000.

Investigators hope the reward money will get some response either from those helping or those who know where he's hiding.

"He's hiding from us. He knew we were after him; that's what makes him extremely dangerous," Whitman said. "He's probably hiding somewhere with a friend of his and that's why we're putting the reward out there also ... I don't think the community needs motivation to turn him in, but I think the criminal element does. And I think the cash will put information forward that will be the tip we need."

Since then, calls about possible sightings have poured into the police department. Someone thought he was on a bus so police searched there, and another person reported Brents was hiding out at an apartment building, so officers were sent to that scene.

"We are following up on all those tips and that means we have to be moving quickly and mobile and have to be able to address what is going on," said Denver police spokesman Sonny Jackson.

All law enforcement agents have been placed on alert to be aware and look for Brents.

"It's something you don't even really think about. When you come across people that look suspicious or someone who fits the description, it is something that just snaps in your head," said Arapahoe County Sheriff Rich Bohm.

Police say Brents may look different from the mug shots that have been released. (See Brents' Many Looks.)

"We anticipate that he has altered his appearance. He's probably without the mustache. He typically wears glasses but he's going to change his behavior so he doesn't get detected," Whitman said.

Police said Brents may also use his aliases, Michael James Curtis or Michael James.

On Friday afternoon, the Arapahoe County district attorney released an audiotape containing Brents' voice, hoping this recording will help them find Brents. The tape is a clip from a phone call between Aurora police and Brents back in November.

Sources told 7NEWS that the more law enforcement investigators learn about Brents, the more they realize he has a talent for fabricating stories and getting people to believe them. During the past 48 hours, police have tracked down several tips from Brents' friends and acquaintances and they all have been dead ends. Investigators believe the friends and acquaintances are telling the truth but were misled by Brents.

7NEWS also learned that Brents hasn't been seen in Denver since Monday, when he got money from a friend. Law enforcement sources also said they believe there may be more victims since Brent was released from prison in July and there may have been more victims prior to his arrest in 1988.

Denver police on Friday obtained an at-large federal arrest warrant for Brents in case he is found in another state so that officials in that state can arrest and hold him until Denver police can extradite him.

On Thursday night's community meeting at Bromwell Elementary, residents where three of the recent attacks occurred asked Whitman questions about the suspect and tried to find out why Brents wasn't on anyone's radar, especially since the known sex offender was accused of an assault in Aurora in November.

After that accusation, Aurora police interviewed Brents twice. They said Brents admitted during one of those interviews to sexual contact with an 8-year-old boy, but he was never detained despite his confession. He had said that the sexual contact was unintentional, occurring as he slept on a bed with the boy and the boy's mother, who was his girlfriend at the time.

It wasn't until 79 days passed -- on Jan. 26 -- when a judge finally signed an arrest warrant for Brents. On Feb. 11, Aurora police inform Denver police that they were looking for Brents on charges of sexual assault on a child. That same day, two women were raped in two separate attacks in a upscale Denver neighborhood. With DNA evidence, police linked those two attacks to Brents.

The most recent attack of which Brents is accused of being involved occurred Monday about 7:45 p.m, when a man armed with a knife broke into a home and sexually assaulted three people.

When he was in his teens in the late 1980s, Brents was arrested for the rapes of a 6-year-old boy and a 9-year-old girl. He spent time in a mental hospital (as a sex offender acquitted by reason of insanity) and then spent 15 years in prison for sexual assault. He was released in July 2004. Less than four months later, he was accused of molesting the 8-year-old boy in Aurora.

Even though he had registered as a sex offender in Aurora, that boy's mother didn't know that he was a convicted pedophile and didn't blink when her new boyfriend bought her son an expensive new bike and offered to baby-sit when she went to work, she said in the arrest affidavit.

Responding to criticism, Aurora Police Chief Richard Bennett defended the length of time it took his department to go from the mother's accusation to Brents' arrest warrant. He said Brents was allowed to leave because additional investigation was needed.

Arapahoe County District Attorney Carol Chambers said she will work to speed up the process of getting a warrant in high-priority cases.

Investigators are looking into other unsolved rape cases in the metro area to see if Brents is linked to them.

"With the intensity of this search, I'm confident that we will find him," Whitman said.

Meanwhile, 6th Avenue Pet Supplies -- the store where one woman was attacked last Friday afternoon -- is scheduled to host a "Take Back the Neighborhood" rally at 2 p.m. Saturday.

Brents is 5 feet 8 inches to 5 feet 10 inches tall and weighs 170 to 180 pounds. He has brown hair and glasses. Police say he has several tattoos -- including a square with two crosses on his lower left outer arm and a hook on his lower left inner arm. His upper right arm has the initials P.B. or B.B.

Police said Brents should be considered armed and dangerous because he is a man with nothing to lose.

Anyone with information on Brents is asked to call Crimestoppers at (720) 913-7867.

Additional Information:

A list of the state's most violent sexual offenders can be found on the Colorado Bureau of Information's Web site. However, only violent offenders, repeat offenders, and offenders who have not registered are listed.
To get a list for your neighborhood, visit your local police department and ask to see the sex offender registry. There's usually a small handling fee involved. A few cities and counties have this list online. You'll need to check with your police department to see if you can access this online.