BOULDER, Colo. -- A Boulder couple who stabbed and beat a suspected intruder to death last week will not face any criminal charges, the district attorney announced Monday.

The man who died allegedly tried to force his way into the couple's home on Poorman Road, just off Sunshine Canyon Road, on the evening of Oct. 3. The homeowners fought back with a metal baseball bat and the intruder's own knife.

"I have consulted with members of the (sheriff's) department and reviewed the evidence available at this time, including witness statements, examination of the crime scene, physical evidence and the 911 tapes. Based upon my review, our office believes the homicide to have been justified, and will not be filing criminal charges arising from this incident," said First Assistant District Attorney Pete Maguire.

Maguire said Colorado law allows a person to use deadly force in cases of self-defense if they believe they are in imminent danger.

The identity of the man who was killed is still unknown. The motive for the violent home invasion also remains a mystery.

According to the sheriff's department, here's what happened:

The masked man rang the doorbell of the couple's home just before 10:30 p.m. Becci Starr, 59, was getting ready for bed as her as her husband escorted their daughter to her car as she was preparing to leave. When Starr heard the doorbell ring, she initially assumed that her husband, Scott Mattes, 56, accidentally locked himself out of the house.

As she approached the front door, Starr said she heard a man's voice say something to the effect of "Boulder county police." When she opened the front door, a masked intruder pushed the door open, pinning Starr against the wall behind the door.

Starr saw that the man was armed with a handgun and a flashlight so she reached a metal baseball bat that had been sitting by the front door -- a bat that had been there for the past 26 years. As Starr armed herself with the bat, the man dropped the flashlight and what was later determined to be a plastic gun, and grabbed a hunting knife from his satchel, deputies said.

Starr screamed for help as she struggled with the intruder and pulled off his mask. She used the end of the bat to push the intruder back outside but he wasn't budging.

"And I'm still saying to him, 'Look, you don't want to do this. What are you, crazy? Get out of here," Starr recounts in a 911 call. "I am so incredulous that I hit this guy so many times and he kept on coming. I couldn't even believe it."

Mattes, hearing his wife's screams, ran upstairs from the basement and immediately charged the intruder, tackling him near the door, authorities said. The two men wrestled with one another on the ground and at one point, the intruder gained a position of advantage on top of Mattes, who was struggling to keep the man from stabbing him, deputies said.

Mattes tried to push the hand and arm of the intruder away as his wife hit the masked man repeatedly with the baseball bat on the head and back.

During the struggle, the intruder dropped the weapon and Mattes was able to gain control of the knife.

At this time, Starr ran back into the house and tried to call 911. But she ran back to the front door seconds later and found that her husband had been pepper-sprayed by the masked man and was again struggling for control of the knife.

Starr again resumed striking the intruder with the baseball bat in an attempt to defend her husband, she said.

Starr said she recalled saying to her husband, "Don't kill him," to which her husband replied, "He's killing me."

As Starr was repeatedly beating the man with a bat, Mattes was underneath him, stabbing him from below. The man eventually stopped being aggressive and at that point Starr and Mattes stopped striking and stabbing the intruder.

Once the man was no longer combative, Starr again returned to the house and was able to complete a 911 call.

In the call, she told the 911 dispatcher, "I have never felt so violated. I was hitting him over the head. Like, I must have hit him 20 times. I have a baseball bat at my front door, and the guy kept coming at me. And then my husband came, and he tried to cut him up. This guy, I'm telling you, I've seen a lot of movies, it takes a lot to take someone down."

Starr was talking rapidly, saying she wanted help to arrive soon.

"I'm so terrified he's gonna die," Starr told the 911 operator. "I don't want that on my life, you know?"

"He has multiple stab wounds, I'm sure of it," Starr said. "Because I'll tell you something, my husband was in a rage. I hope it's not like a bad thing. I mean this guy came into our house, and I'm freaking out now because he's (expletive) dying in my front yard."

"I don't know how much time has passed, but let me tell you, I feel like I was just in an action movie, you know. And I watch a lot of films. It was like so unreal," she said. "He says he's having difficulty breathing, but you know, do I care? I mean, this (expletive) guy came into my house."

When she returned, her husband was at the front entryway of the home, trying to resuscitate the intruder.

Mattes continued rendering medical aid to the assailant until deputies arrived.

The entire struggle was less than five minutes -- about the time a neighbor across the street called 911, saying she could hear someone being hit with a bat, until the deputies arrived at the scene.

Investigators say the intruder had arrived at the couple's home by bicycle, and had armed himself with a toy water gun, the knife and pepper spray. He also had with him a green satchel containing small sections of rope, duct tape and zip ties, according to the sheriff's department.

Inside the satchel was a sheath for a hunting-style knife, which is consistent in size with the knife that had been used to attack the couple.

The intruder had been wearing a shirt with eye holes cut that was fashioned into a mask.

"The circumstances of this incident reveal a clear case of self-defense and defense of others. Mr. Mattes and Ms. Starr were each acting to protect the other from the actual use of force from the knife wielding assailant. The belief that the homeowners were in imminent danger of death or great bodily injury is obvious. The ferocity of the attack left no doubt that if they had not defended themselves effectively they would likely have been killed. The amount of force used was not excessive. The intruder refused to disengage from his assault and in fact did not cease his physical aggression until he was very near death. Mr. Mattes even attempted to perform CPR on the assailant after he ceased fighting," said Maguire.

Neighbors said Mattes and Starr are peaceful people and even a Buddhist sign on their property reads, "May Peace Prevail on Earth."

The couple still does not know why they were the subject of a home invasion.

The intruder's fingerprints were run against FBI's files and records for the Colorado Bureau of Investigation, but no match was found.

The intruder was described as a Caucasian male, possibly Hispanic, in his late 20s or early 30s. He had a muscular build, and was approximately 5 feet 10 inches tall and weighed 175 pounds. He had brown eyes and short, wavy brown hair.

The man had a scar under his chin and a series of irregularly shaped, non-surgical scars on his right thigh. He also had a red tattoo on his right ankle.

Anyone with information about the man's identity or his motive was asked to call Detective Steve Ainsworth at (303) 441-3627.