The man wanted in the murders of three people in south Lakeland over the weekend has died, according to the Knox County Sheriff's Office.

David Eugene Smith, 27, was captured in Knoxville, Tenn., Tuesday after he wounded himself during a SWAT standoff, authorities said. He was apprehended at a Days Inn motel, according to authorities.

The cause of death appears to be a self-inflicted gunshot wound. An autopsy is scheduled for Wednesday.

Knox County Sheriff's Office Maj. Mike MacLean said Smith called the agency around 11 a.m. and said he wanted to commit "suicide by cop." A SWAT team and other law enforcement members then responded to the motel.

"It's a little unusual for a subject to call in himself and give his location and tell you he wants to commit suicide by police," MacLean said. "It has happened before. Obviously, it's a very volatile situation - someone that's predisposed to that kind of violence."

MacLean said Smith fired two shots from the motel room and a third shot that stayed within the room. After a period of silence, deputies threw a tear gas canister into the room, went inside and found Smith still alive.

Smith was captured around 2 p.m. and taken to a local hospital. The beige Mercury Sable he was driving and a firearm were impounded, authorities said.

Polk County Sheriff's Office detectives named Smith as their suspect after two women and one man were found shot to death late Monday at a home in the 5600 block of Old Road 37, near Cherry Lane and Schoolhouse Road.

The victims were identified as Eugene Smith's sister Danyala Smith, 31; Miranda Mims, 28; and Nikosi Williams, 25.

Danyala Smith and Mims lived at the home. Danyala Smith's 14-year-old daughter found her mother's body after returning home from a Memorial Day weekend trip, Polk County Sheriff Grady Judd said.

“She was only 14 when she walked in on this murder scene. And that is horrific for anyone. Especially a child,” Judd said.

Judd said the shootings may have happened Saturday and that authorities believed Smith was headed to Texas or Tennessee, where he has family.

The sheriff said Eugene Smith served in the Army's 82nd Airborne Division in Iraq and Afghanistan, suffers from post-traumatic stress disorder and had been Baker Acted in the past.

"More often than not, the people we end up in a violent dust-up with (are) not the guy who goes in to rob the bank," Judd said. "It’s the mentally ill person with a firearm or knife that has not received appropriate help.

"He (Smith) checked all the boxes: paranoid, delusional, posted rants on Facebook. We’re learning from California (last weekend shooting rampage there), when you see something, say something."