BUFFALO, N.Y. >> Surgeon Timothy Jorden saved the lives of patients with gunshot wounds, lived in a big home by Lake Erie and owned four vehicles. He was a product of a working-class neighborhood who became an Army officer before coming home to earn his medical degree.

Now the healer is linked to a killing.

Police across the country were on the lookout Thursday for the 49-year-old trauma surgeon in connection with the shooting death of his ex-girlfriend in a building at the Buffalo hospital complex where they both worked. Police say the former Army weapons expert may be armed and should be considered dangerous.

“He was an excellent surgeon. He saved so many lives. For him to take one is unreal,” said a stunned June DuPree, a neighbor of Jorden’s in an exclusive cluster of homes on a lakefront bluff.

But she and others also said the affable and accomplished doctor seemed different lately — thinner, not quite as friendly and less meticulous about appearances. Friends of the victim, meanwhile, offered glimpses of a much darker side.

“I saw him at the beginning of the season and noticed how much weight he had lost,” DuPree said. “He said, ‘Yeah, I lost a little bit.’ But it was more than a little bit. It was a lot. He wasn’t too friendly that time I saw him. He just didn’t want to talk.”

The search for Jorden began Wednesday morning when 33-year-old Jacqueline Wisniewski was found shot to death in a stairwell on the campus of the Erie County Medical Center. Police say she was shot four times.

Heather Shipley, a friend of Wisniewski, told WIVB-TV that Wisniewski feared Jorden and that he wouldn’t let go after she left him because she believed he was having affairs with other women.

She said Wisniewski told her the doctor had put a GPS tracking device in her car and once held her captive in her home for a day and a half, wielding a knife.

“She told me if anything happened to her, that it was him,” Shipley told the station.

Jorden had been involved in two domestic incidents in neighboring Cheektowaga in 2003, police Capt. James Speyer said. He said he couldn’t release details but that the incidents did not involve Wisniewski.

Buffalo Police Commissioner Daniel Derenda on Thursday called Jorden “a person of interest” in the administrative assistant’s death and said a nationwide alert had been issued advising police agencies that he was wanted for questioning. Officers combed through the grounds outside his home and for a second day, an Erie County Sheriff’s helicopter circled overhead.

At one point, police dogs were seen near a ravine and neighbor Tom Wrzosek told The Associated Press he’d reported hearing a single shot around 9:30 a.m. Wednesday, which he initially dismissed.

“Then my girlfriend mentioned if he committed suicide, someone would have heard it,” he said. “That kind of rang a bell.”

Derenda said all of Jorden’s vehicles were accounted for and investigators were certain he had not crossed the nearby border into Canada.

“He’s out there somewhere,” he said.

The search comes after a lifetime of achievement for the divorced father of a grown son.

Jorden had been profiled in The Buffalo News as a homegrown success story in 1996 and was among those honored with Buffalo’s Black Achievers in Industry award in 2002. As a surgeon at the city’s main trauma hospital, he worked long hours and was always ready to respond to a hospital emergency when his cellphone rang.

In his Lakeview neighborhood south of Buffalo, Jorden was described as a friendly neighbor with a busy schedule. Neighbors said he clearly spent a lot of money to keep the grounds of his white, gabled home by the lake manicured and lush.

Things changed dramatically this spring.

Jorden’s bushes became overgrown, his grass grew knee-high and a kitchen remodeling job was halted. Jorden, a big man, had lost dozens of pounds. Neighbors thought he was sick.

“He had a lot of money invested in his house and the landscaping. And when I came back from Florida in May, it was really neglected. I was just shocked,” said Wrzosek, the neighbor.

“We presumed he was sick, that maybe he had some sort of major ailment,” Wrzosek said.

“He was sick,” he said. “But not in the way we thought he was sick.”

Jorden joined the National Guard in high school, went into the Army after graduation and served with the Army’s Special Forces, first as a weapons expert, then as a medic, according to the News.

“Everybody’s been made aware of his training and background,” Derenda said, “so when individual officers approach him, they’ll take proper precautions.”

Jorden later attended the University at Buffalo’s medical school and did residencies at Madigan Army Medical Center in Tacoma, Wash., and the Morehouse School of Medicine in Atlanta. Derenda declined to speculate on whether he may have returned to those areas.