The Baseline Killer shot his victims in the head, sometimes using either medium- or largecaliber weapons, according to examinations of victims in five of the six fatal shootings attributed to him.
The city’s other serial killer used small-caliber weapons or a small-gauge shotgun in three of five fatal shootings, the reports said. The five victims linked to the Serial Shooter were hit in the torso or neck.
The reports released Wednesday by the Maricopa County Medical Examiner’s Office provide a glimpse into the massive police investigation of killings that have gripped the Valley and put community block watch groups on high alert.
The two predators are suspected of randomly attacking at least 41 people. The Serial Shooter is thought to have first killed in May 2005 and has targeted dogs and horses as well as people. The Baseline Killer is believed to have begun killing in September.
According to the autopsies, the victim of at least one shooting linked to the Baseline Killer was attacked from close range. Autopsies from two of the five shootings mentioned that a medium- or largecaliber bullet was used.
There was no mention of what caliber bullet was used in the other three slayings.
Another Baseline Killer shooting involved one or more gunmen, according to the medical examiner’s office.
The autopsy of Tina Marie Washington said a nearby business owner saw ‘‘suspects’’ standing over Washington with a drawn handgun.
Ronald R. Scott, a Phoenix firearms and ballistics expert who reviewed some of the reports for The Associated Press, said that the Baseline Killer is either an excellent shot, or that his victims had no idea he was about to attack.
‘‘Shooting someone in the head is like aiming at a balloon in the wind,’’ Scott said. ‘‘And if I saw someone aiming at me, I would certainly be doing some evasive action.’’
Police spokesman Sgt. Andy Hill said that the Baseline Killer sometimes had a brief exchange with victims just before striking. Hill would not discuss specifics.
That means that in many of the killings and sexual assaults attributed to the killer, there may have been an opportunity for the victims to get away.
‘‘People do get intuitive feelings, and they do need to follow those feelings,’’ Hill said.
Katherine Ramsland, a professor at DeSales University in Pennsylvania who teaches about serial killers, said there could be two reasons the Baseline Killer talks to victims before striking.
‘‘He’s probably checking out how vulnerable they seem, whether they’re seeming to be on guard, armed with a weapon or alone,’’ Ramsland said.
‘‘And he’s picking out certain types of people who are satisfying something for him, fitting a particular criteria that fulfills his inner fantasies.’’
Scott said the S erial Shooter probably is less selective and is simply trying to hit somebody.
On Wednesday, Phoenix police continued to check thousands of tips in the case.
Silent Witness director Paul Penzone said the number of calls have dropped in recent days, with more than a week since the last attack.
The city’s Silent Witness hot line received about 1,000 calls per day shortly after Phoenix Mayor Phil Gordon made a public plea for information last week.
The center now gets about 300 to 500 calls per day.
During a news conference, Hill advised Phoenix residents to leave or call police if they ever get a strange feeling about something.
He said police would rather chase down a false lead than investigate another
An autopsy for the Baseline Killer’s sixth victim, Carmen Miranda, was not available Wednesday.