ODESSA, Texas —A 23-year-old man accused of the aggravated sexual assault of a 9-year-old autistic Odessa girl has been sent to a state mental hospital after experts determined he was incompetent to stand trial.

District Judge John Smith ordered Dwayne Dale Billings, a registered sex offender, to stay at least 120 days in the North Texas State Hospital in Vernon. Monday’s ruling was based on the opinions of two experts who evaluated Billings.

Defense psychologist John Howlett said Billings was not able to help in his defense, according to Ector County District Attorney Bobby Bland. Another expert for the prosecution, Perry Marchioni, agreed with Howlett.

“We expect him to go down to the Vernon state hospital and go through their program there so he can be found competent to be able to stand trial,” Bland said in a story in the Odessa American’s online editions Monday.

Defense attorney David Zavoda said he didn’t know if Billings’ time in Vernon would help.

“He’s got a long history of mental health issues that have been addressed through the years,” Zavoda said.

Billings faces up to life in prison if convicted on the aggravated sexual assault charge. He is also charged with aggravated kidnapping and criminal trespassing. He is still in the Ector County Detention Center on bonds of $1.5 million.