FRESNO (CBS SF/KGPE) — Ten people were shot, four fatally, in what police are calling a “mass casualty” shooting at a backyard Sunday Night football watch party in southeast Fresno, Fresno police said. Reports of shots fired first came in around 6 p.m. near Peach and Olive Avenues, Fresno Police Lt. Bill Dooley told CBS Fresno affiliate KGPE-TV.

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While officers were heading to the scene, more reports of shooting victims came in.

The “family” gathering was a backyard watch party for Sunday football games. Dozens of people, about 35, were there, including women and children. Police said none of the children were hurt.

The suspected shooters were able to sneak into the backyard and open fire, Dooley said. Four men are dead–three were found dead in the backyard and the fourth victim died at the hospital, police told KGPE.

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All of the victims are Asian males aged 25-30, police said.

“We’re going to exhaust every investigative lead we can to find out who did this, why they did this, and bring those folks to justice,” said Michael Reed, deputy chief of the Fresno Police Department.

Reed called the shooting “senseless violence” and “likely targeted.”

Others who were injured were taken to Community Regional Medical Center in critical condition and some are in critical but stable condition. Family members of the victims were gathered at the hospital early Monday.

No suspect information was released as of Sunday evening. An increase police presence in the neighborhood was noticeable Monday morning.

Agents from the U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives field office in San Francisco would be on the scene Monday morning, aiding in the investigation.

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Anyone with information about the shooting was asked to call Fresno PD at 559-621-7000.