TULSA, Okla. (AP) — Police believe the same attacker or attackers are behind a series of early-morning shootings in which three people were killed and two others were critically wounded within a three-mile span of north Tulsa.

Homicide detective Sgt. Dave Walker said investigators don't have the results of forensic tests yet, but police think the early Friday morning shootings are linked because they happened around the same time in the same general area and all five victims were out walking when they were shot.

Police don't believe the victims knew one another and are trying to determine the circumstances behind the killings.

All five victims are black, and black community leaders met Friday evening in an effort to calm unrest and promote safety. NAACP Tulsa president, the Rev. Warren Blakney Sr., told the Tulsa World (http://bit.ly/HgxIXn ) someone appeared to be "targeting black people to shoot."

"I'm on edge for my people," Blakney said.

Four shooting victims were found in yards, and the fifth in a street. Police identified those killed as Dannaer Fields, 49, Bobby Clark, 54, and William Allen, 31. Fields was found wounded about 1 a.m. Friday, Clarke was found in a street about an hour later, and Allen was discovered in the yard of a funeral home about 8:30 a.m.

Minutes after Fields was found, police found two men with gunshot wounds in another yard two blocks away. They were taken to hospitals in critical condition but expected to survive, police said. Their names have not been released.

Police Capt. Steve Odom said in his 30 years with the police department, he'd never seen so many shootings happen in such a short time.

Walker said detectives interviewed people Friday afternoon in the neighborhoods where the shootings happened and believe a white man driving a white pickup truck may have been involved.

Tulsa City Councilor Jack Henderson urged people to be cautious but not let "some crazy, deranged person mess up their weekend."

"There's no need to become a vigilante," Henderson said, adding that he has been assured police are working on the case as a "24/7 round-the-clock deal."