The attorney for a homeless man charged in the killings of his mother, sister and a family friend in a knife and hammer attack Saturday in a Hempstead home may use an insanity defense, his lawyer said Wednesday.

Bobby Vanderhall, 34, didn’t appear in a Mineola court as attorneys for the prosecution and defense held a brief conference with the judge on his case.

Police arrested Vanderhall on Saturday, charging him with second-degree murder in the deaths of his mother, Lynn Reichenbach-Vanderhall, 58; his sister, Melissa Vanderhall, 29; and Melissa’s friend, Janel Simpson, 29, of Uniondale.

He also faces an attempted murder charge for allegedly attacking a fourth woman, Candace Murray, who also was a friend of his sister. Police said she was able to flee the Vanderhall family’s Perry Street home after suffering a head and hand injury.

Authorities have alleged Vanderhall attacked his mother with a knife and hammer and bludgeoned the other women with the hammer.

Vanderhall’s attorney, Derrick Magwood of Mineola, also said Wednesday in a Newsday interview that his client told him he suffers from schizophrenia.

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Magwood said the defense was starting its own investigation of the case that would include seeking information on Vanderhall’s medical history.

Police have said the defendant has a history of “emotional issues,” that his mother had held an order of protection against him, and recently had kicked him out of the family’s house.

“There’s definitely a history of mental illness,” Magwood said, adding that extended family members of his client who hired him to represent Vanderhall didn’t have specific details about the man’s medical history.

“They didn’t expect anything like this so obviously they’re concerned for him,” he added.

A spokeswoman for the district attorney’s office declined to comment Wednesday.