A California couple is recovering from serious injuries after their adoptive son allegedly stabbed them at their home early Tuesday.

KABC reported that police are investigating whether mental illness played a role in Matthew Boulet stabbing his fathers, Ken Coll and Tom Boulet, at their Sherman Oaks home. Matthew allegedly stabbed the pair with a folding pocket knife that had a blade measuring three to four inches.

While it’s unclear how many times the couple was stabbed, KCAL reported they were initially hospitalized in critical condition and have undergone surgery. However, they are expected to survive.

Another thing that’s unclear is what led to Tuesday’s stabbing. Michael, 21, was reportedly home from college for summer break at the time. Officers who responded to the home found Michael with blood all over his face and the weapon believed to have been used in the crime.

The injured couple’s son, who reportedly lacerated his hand during the attack, is currently facing attempted murder charges.

“He was very nonchalant when he said he had stabbed his two fathers and that he suffered a wound while doing so,” Los Angeles police Lieutenant Mike Kozak said. “He was very calm about it.”

[Featured image: Ken Coll and Tom Boulet/KCAL video screenshot]