GRAND JUNCTION, Colo. -- Police Monday remained baffled as to why a man who grew up in Alaska and was staying with a relative in suburban Denver apparently drove 240 miles to kill a dentist and the wife of a former Mesa State College President.

The spouses of those killed survived Saturday morning's shooting in the driveway of a home near a country club, about a mile from an Interstate 70 exit.

Investigators said the shooter, 22-year-old Stefan Alexander Martin-Urban, followed two of the victims before opening fire.

Acting Chief Troy Smith said Martin-Urban followed Michael Gallagher and his wife Floyce to the home of Terry Fine and his wife Linda.

The couples were going to go on vacation.

Terry Fine, 61, a dentist and Floyce Gallagher, 60, both died in the shooting. Michael Gallagher, who was not hurt, drove a wounded Linda Fine to St. Mary's Hospital, where she was listed in good condition.

Investigators determined Martin-Urban fired more than a dozen rounds, some from close range, from a 9mm handgun and reloaded at least once. Investigators believe he had ammunition and spare magazines in a canvas bag he was carrying.

Martin-Urban died Sunday around 1 p.m. of a self-inflicted gunshot wound. He had no criminal history, no ties to the Grand Junction area and no apparent link to the victims.

Smith said Martin-Urban bought the gun used in the shooting from Green Mountain Guns in Lakewood on Oct. 2. Store manager Keith Martin confirmed the purchase and said the store had spoken with police, but he declined further comment.

Receipts found in his jeep showed that he bought gas at a Grand Valley gas station Friday morning and then traveled to Green River Utah where he bought food, Smith said.

Police had received about a dozen tips by Monday morning but Porras did not immediately have details.

The Denver Post reported that Martin-Urban grew up in Fairbanks and graduated from Lathrop High School.

A woman who answered the phone at the home of Martin-Urban's mother Sunday read a statement to the paper: "The family of Stefan Martin-Urban extends their heartfelt condolences to the families of the victims and requests their privacy be respected as they grieve their losses."

Police say Martin-Urban had been living with a relative in the Denver suburb of Lakewood for the last seven weeks after moving there from the Los Angeles area.

"What (Mike Gallagher) had in the forefront of his mind was to save as many people as he could," Grand Junction Police Chief Troy Smith said of his conversations with Michael Gallagher following the shooting.

The Fines' neighbor, who ran to the home to help after hearing the shots, also was shot but was out of the hospital Saturday night.

Police executed search warrants at Martin-Urban's home and the Fines' home but would not say what they found in the homes or in the suspect's vehicle.

No suicide note has been found.

Michael Gallagher served as president for academic affairs at Idaho State University from 1989 to 1996, and as interim president in 2005. Floyce Gallagher, 60, is a former Idaho middle school teacher who retired this year.

Kent Tingey, a longtime friend and ISU colleague of Michael Gallagher, said the couple planned to spend more time traveling now that they were retired.

"She was a wonderful woman. She had a great sense of humor," Tingey told the Idaho State Journal.