A Baton Rouge man suspected of fatally shooting three homeless people in December will be examined by a doctor to help a judge decide whether he was sane at the time of the killings and can assist his attorney.

Jeremy Anderson, 29, pleaded not guilty back in March to a first-degree murder charge in the slaying of Tony Williams, but his lawyer said several months ago that Anderson intends to enter dual pleas of not guilty and not guilty by reason of insanity.

State District Judge Tarvald Smith late last week appointed Dr. John Thompson to evaluate Anderson and issue a report on his sanity at the time of the offense and whether he can help his attorney, Carson Marcantel, in the preparation of Anderson's defense.

Dr. Jose Artecona previously ruled in a theft case involving Anderson that he was not competent to proceed in that case.

Marcantel has said Anderson "did not know right from wrong" when he allegedly shot Williams to death at a vacant house.

Smith has scheduled a sanity hearing for Jan. 11.

East Baton Rouge Parish District Attorney Hillar Moore III has said his office will prosecute Anderson as an alleged serial killer and introduce evidence of the Dec. 13 killings of Christina Fowler and Gregory Corcoran at Anderson's trial in the Dec. 27 slaying of Williams.

Moore has not indicated whether his office will pursue the death penalty. If it chooses not to, Anderson would be sentenced to life in prison if found guilty of first-degree murder.

Fowler, 53, and Corcoran, 40, were found dead beneath the North Boulevard overpass. They were huddled in blankets beside an empty shopping cart less than a block from Anderson's home on South 17th Street.

Williams, 50, was discovered two weeks later shot to death on the front porch of a vacant home on 18th Street near Convention Street. That home is a few hundred feet from Anderson's home.

All three victims were shot in the head.

Anderson was arrested in early January in the slaying of Williams and in the killings of Fowler and Corcoran after officers received information from someone who heard him confess to the killing of Williams, Baton Rouge Police Chief Murphy Paul has said.

Detectives executed a search warrant at Anderson's home and seized evidence linking him to the crimes, Paul said.

When officers questioned Anderson he made incriminating statements that placed him at the crime scene, the chief said. Anderson's arrest report says that while giving a statement to detectives, he confessed to killing Fowler and Corcoran.

Williams, Fowler and Corcoran were killed in an area where many of Baton Rouge's homeless residents congregate because of its proximity to several shelters and other service providers.

Police do not have a motive for the slayings, and it's not known whether the victims were killed at random or specifically targeted — either for being homeless or for some other reason. Police said they weren't sure whether Anderson knew the victims.

Anderson's criminal history in East Baton Rouge leading up to the killings included two misdemeanor convictions: one for illegal carrying of weapons in 2013 after officers found him with a stolen gun, and the other for simple battery in 2014 after his arrest on domestic abuse counts.

Email Joe Gyan Jr. at jgyan@theadvocate.com.