Updated: Explosion at Mattel Design Center in El Segundo

Updated 10:10 p.m. April 30

An explosion inside the Mattel Design Center building Tuesday morning is being investigated by El Segundo police and fire departments, as well as the Los Angeles County Sheriffs bomb squad, said El Segundo Police Department Capt. Bob Turnbull.

The explosion, which police believe came from a small plastic bottle in the northern area of the one-story building at 2031 E. Mariposa Ave., did not injure anyone, he told Patch.

The design center was evacuated and police issued an advisory for the public to avoid Mariposa between Nash St. and Continental Blvd. during their investigation.

Turnbull described the explosion as "more of a sound explosion" and said the structure had not been damaged.

Mattel security heard the explosion and found debris sometime around 7 a.m. Turnbull believes there were no employees other than security inside the building at the time.

The explosion is being investigated as a crime; police are interviewing employees and will review all video.

Mattel employees were allowed inside the building after it was determined to be safe to do so.

The bomb was described as a homemade plastic explosive device. Police ask anyone with information to contact Detective Eric Atkinson at (310) 524-2216 or eatkinson@elsegundo.org.