Aliso Viejo, California (CNN) The deadly explosion in an Orange County building that killed one woman and injured three others appears to be intentional and is being investigated as a criminal act, a law enforcement source told CNN.

But the source also cautioned that it's early in the investigation.

The Orange County Sheriff's Department stated in response to news reports: "Despite media reports quoting unnamed sources, we have not confirmed that the explosion is intentional, nor have we conclusively identified the source of the explosion. Investigation is in early stages, as information is confirmed we will share it."

The explosion rocked a medical building in Aliso Viejo, California, on Tuesday. It blew out walls and windows, heavily damaging the first floor corner of the two-story building and hurling debris outside, said Capt. Tony Bommarito, a spokesman for the Orange County Fire Authority.

In a news conference Tuesday night, Orange County Sheriff's Department Commander Dave Sawyer said it was unclear whether the explosion was intentional or accidental.

Read More