Benji Gregory, the former child star famous for his role on the 1980s sitcom “Alf,” has passed away at the age of 46.

According to Gregory’s sister, Rebecca Hertzberg-Pfaffinger, who spoke to The New York Times, the actor and his service dog, Hans, were discovered dead in his car on June 13 in a Peoria, Arizona parking lot. While the cause of death is still under investigation, Hertzberg-Pfaffinger suggested in a Facebook post that her brother likely fell asleep in the car and died from heatstroke.

“Alf,” which aired for four seasons from 1986 to 1990, featured Gregory as one of the Tanner family children who befriended Alf, an Alien Life Form that crash-landed into their garage. The show also starred Max Wright and Anne Schedeen as his parents, and Andrea Elson as his sister.

Born Benjamin Gregory Hertzberg in Encino on May 26, 1978, Gregory came from a family of actors—his father, uncle, and sister all acted, and his grandmother was his agent, according to IMDb.

Gregory appeared in numerous commercials and 1980s TV shows, including “The Twilight Zone,” “The A-Team,” “Punky Brewster,” and “Amazing Stories.” In 1986, he played Harry Carlson Jr. in “Jumpin’ Jack Flash,” starring Whoopi Goldberg, and voiced Edgar the mole in the 1993 animated movie “Once Upon a Forest.”

He left Hollywood and in 2004 became an aerographer’s mate for the U.S. Navy in Biloxi, Mississippi, according to IMDb. His sister told the Times he struggled with bipolar disorder and depression and received treatment for both conditions.