Lakewood police launched a search through Fort Steilacoom Park on Friday after a woman reported an armed man grabbed her from behind.
The man was not found.
Police said the woman was grabbed just before 2 p.m. She screamed, then the man pushed her down and ran off. A person who was nearby heard her screams and ran to help.
Police searched the area with K9 dogs, with help from a Washington State Patrol aircraft. They also checked vehicles leaving the park, and three nearby schools were placed on a brief lockdown.
The man was described as white, in his 20s, with a thin, muscular build. He had a distinctive blue or purple tattoo in the shape of a sun on his chest. He was not wearing a shirt, but did have on a blue and brown knit cap and blue jeans.
Clover Park School District spokesman Gary Sabol said the lockdowns lasted about 10 minutes at Lakes High, Lake Louise Elementary and Mann Middle schools.
He said the incident might have delayed some school buses, because those that had arrived at the schools at dismissal time were asked to stay on campus during the lockdown.
Sabol said parents at the three schools were notified of the incident by email or phone.
Police asked anyone with information about the suspect or the incident to contact them.