PASADENA (CBSLA.com) — Authorities say an investigation was underway Sunday after police officers came upon a human skull and other bones in Pasadena.

Pasadena police Lt. Clawson says police responding to a “trespassing” call made the discovery about 12:50 p.m. Saturday.

According to Clawson, the artifacts were found at a makeshift altar in a detached garage in the 800 block of N. Oakland Avenue.

Other items, including burned artifacts and animal bones, were also recovered.

The altar was adorned with incense and candles, Pasadena police said in a department statement. Authorities say they’ve since collected the items.

No one arrested and it’s not clear whether a crime was committed.

The Los Angeles County Coroner’s office along with Pasadena police are investigating.

The statement said, “This incident is being investigated as suspicious circumstances and is on-going.”

Brittney Hopper, reporting for CBS2 and KCAL9, spoke to neighbors who said they were not surprised about the findings. One neighbor, who didn’t want her name or face used, said at least once a week, she heard loud chanting coming from the backyard of the home. She said she’s also seen many cow and goat heads “and blood all over the place.”

Other neighbors said the homeowners wouldn’t hurt anyone or anything. Said one man, “They are harming no one. It’s just a basic religious ritual they are performing.”

The Humane Society took an undetermined number of live animals from the home while police continue their investigation.

A knock on the door of the homeowner elicited a “no comment.”