Matthew Taylor Coleman, the California father accused of killing his two children with a spearfish gun after believing that they had serpent DNA, has continued to harm himself behind bars — and authorities are seeking to involuntarily administer antipsychotic drugs to restore his competency to stand trial. 

Coleman, now 43, was treated for injuries last month after he slammed his head into the wall, the Daily Mail has learned. He had bitten his tongue. 

The former surf instructor has repeatedly attempted to harm himself, according to court documents. 

Both the prosecution and the defense concede that he has slammed his head into a toilet, repeatedly cut his arms and legs, and punched himself in the face over and over. 

Coleman is on suicide watch, and authorities have removed most dangerous objects from his cell. 

Things have gotten so bad that both the prosecution and defense have agreed to a closed-door hearing on April 15 to discuss the legal issues of medicating him against his will. 

Coleman, who is being held at an undisclosed federal prison in southern California will attend the hearing via teleconference. 

United States District Judge Cathy Ann Bencivengo ordered the prosecution to submit a proposed treatment plan for Coleman last month. 

The plan has been sealed from public record, but family members say that it includes antipsychotic drugs. 

‘He is on some heavy medication now,’ says a relative of Coleman’s wife, Abby, who left California after the killings and is living in Texas with her family. ‘I don’t know how much it has helped yet, but before the treatment, he was babbling a lot, not making any sense. The Matthew we knew and loved was gone.’

Matthew Taylor Coleman was a popular surf instructor in Santa Barbara before the killings.

Coleman has been held for more than 3 years and is still considered incompetent to stand trial.

 Those close to Coleman believe that he had a psychotic break in the summer of 2021, changing him from a devoted family man to someone who was able to commit unspeakable violence against his own kids. 

The Colemans were packing for a family camping trip in August 2021 when authorities allege that he abruptly loaded his two young children Kaleo, 2, and Roxy, 10 months, into his sprinter van and drove away from their home in Santa Barbara, Calif. 

Abby Coleman repeatedly tried to call her husband to ask where he had gone, but he did not answer the phone.  

Authorities allege that Coleman drove the children over the border into Mexico and checked into a resort hotel, where he spent two days holed up in his room. . 

Then, authorities say, Coleman drove the kids to a ranch, where he allegedly stabbed them multiple times with a spearfishing gun. He returned to his hotel a few hours later before attempting to cross back into the U.S. 

But before Coleman could cross the border, a Mexican farmer made the gruesome discovery of the two children’s lifeless bodies. He contacted Mexican authorities who contacted the U.S. Consulate. 

Coleman was arrested at the border as he tried to cross back into the USA.  

According to an FBI complaint obtained by the Daily Mail, Coleman allegedly told authorities that he was motivated by conspiracy theories. A search of his phone showed that he had accessed dozens of message boards and forums that perpetuated QAnon beliefs of evil influences in powerful places. 

Kaleo and Roxy Coleman were stabbed multiple times with a spearfishing gun. 

Abby Coleman has moved to Texas to be with family. She has limited contact with her husband.

‘He was a doting dad before things went bad,’ a childhood friend tells The Daily Mail about Coleman. 

In the complaint, special agent Jennifer Bannon wrote that Coleman said he was ‘enlightened by QAnon and Illuminati conspiracy theories’ and that he spent hours ‘researching’ them every day. 

‘He got very into conspiracy theories,’ a childhood friend of Coleman’s tells the Daily Mail. ‘It became something that he spent a lot of time and mental space on.’  

But Coleman did not merely believe the conspiracy theories about strangers; he told authorities when he was arrested thgar believed that the evil had infiltrated his own family. 

‘He said visions and signs revealed his wife, A.C. [Abby Coleman], possessed serpent DNA ([He] mentioned that he was not sure if his wife was a shapeshifter) and had passed it onto his children and that all things were pointing to the idea that his children have corrupted DNA that will spread if something is not done about it,’ reads the affidavit.

‘M. Coleman stated that he believed that his children were going to grow into monsters, so he had to kill them’ Bannon wrote. 

Coleman was indicted on murder charges and is eligible for the death penalty if convicted. 

He has pleaded not guilty to the charges; the public defender’s office has not returned The Daily Mail’s calls for comment.