photo from media partner 10News

San Diego police are investigating the discovery of about 20 razor blades placed on the grass at a park in Mission Bay.

At about 6:15 p.m., police said a family reported finding razor blades stuck in the ground at Bonita Cove Park.

Police said the single-edged blades were placed in the grass around a popular playground with the sharp side sticking out of the ground. No injuries were reported.

Police canvassed the area Thursday night with a metal detector and collected the blades.       

“Just these random acts of violence like this, just very scary as a parent,” said Steve McMillan, a Rancho San Diego resident.

One witness told 10News he was informed by police that this was a "recurring problem."

10News learned that this is the second time in less than a month that the park was booby-trapped with razors. Last month, 10 blades were found in the same area and a 41-year-old woman was injured. The park was cordoned off as authorities searched the area.

 “It’s a terrible crime that someone would want to inflict injury on someone like that,” said San Diego Police Lt. Paul Rorrison.        

Police said the razor blades were taken from the scene will be tested for fingerprints and sent to a crime lab to see if DNA can be extracted. Officers said they are also trying to determine if the blades from both incidents matched and could be linked together.

“That's just terrible," said McMillan. "It’s terrible that it happens anywhere, terrible that it happens in San Diego. I see the San Diego Police are on it. I know they'll do a good job."

Police said in both incidents, the reporting party wanted to remain anonymous. Police were not sure if that person could be involved. It is something police said they are also looking into.