Brittany N. McAdory, left, and Seairaha J. Winchester, right


Janesville police Thursday still were focusing on a person they believe shot and killed two women Monday, and they still were not saying who that person is.

Lt. Charles Aagaard said investigators want to gather more evidence before naming the suspect.

“We just don’t want to name the wrong person. We want to make sure,” Aagaard said.

The suspect was still at large Thursday. Police have asked law enforcement around the region to be on the lookout for him or her—Aagaard would not give any identifying details about the suspect, including gender.

Police also need more evidence before they have enough to arrest the person or issue an arrest warrant, Aagaard said.

To issue a warrant or make an arrest, police need “probable cause.”

Without probable cause, police cannot arrest someone, even if they meet him on the street, said Donald Downs, professor emeritus at the UW Law School.

Police could confront the person and tell him he was a suspect. They could invite him to come to the police station to answer questions, but the person would be free to go, Downs said.

Downs said probable cause amounts to evidence that would lead a reasonable person to think that a crime was committed by that person.

The approach to determining probable cause comes from a 1983 Illinois case that went to the U.S. Supreme Court, Downs said.

Police had received an anonymous tip about a husband and wife who were selling large amounts of marijuana and bragging about it, Downs said.

The tipster described how the couple would fly to Florida and drive back with the weed. Police followed the couple the entire journey and arrested them when they arrived home.

The couple appealed all the way to the nation’s highest court, saying police did not have probable cause to arrest them. But the high court disagreed.

The court said probable cause must be based on “factual and practical considerations of everyday life on which reasonable and prudent men, not legal technicians, act.”

Police, who deal with this standard all the time, know probable cause when they see it, Downs said.

Aagaard said police are trained in what probable cause means, but it’s not easy to explain.

“It’s more than mere evidence. It’s more than a suspicion,” Downs said. “… When you do this stuff, you get a sense.”

Downs said there’s no law that forbids police from identifying a suspect before they have probable cause, but wanting to avoid naming the wrong person makes sense.

“That’s reasonable. I agree with that, just as a matter of decency I suppose,” Downs said.

Aagaard agreed that naming a suspect would have benefits: People could tell police if they saw him and could better protect themselves from him. Identifying a suspect could ease the concerns of the victims’ families, and it would put to rest rumors that have circulated on social media.

Janesville police quickly identified an at-large suspect in another recent gunfire homicide just last month. They named Corvasie S. Weaver, 24, one day after a fatal shooting on Jan. 5.

Weaver, of Joliet, Illinois, is still being sought.

Aagaard said detectives are using the same process in the earlier homicide as they are with Monday’s killings of Seairaha J. Winchester, 30, and Brittany N. McAdory, 27.

It’s just that the first investigation was faster, Aagaard said.

This one is taking more time.