IRVINE, Calif. (KABC) -- Irvine police are warning the public about a man on a skateboard who has sexually assaulted two female joggers recently.The attacks happened in the city's Woodbury area Sunday and Monday nights, police said. In one incident that happened Sunday around 6:15 p.m. to 6:30 p.m., a woman was jogging in the area of Groveland and Townsend when a man riding past her on a skateboard groped her, police said.The next night around 8:15 p.m., a man on a skateboard matching the same description rode up behind a female jogger at Rolling Green and Statuary. He pushed the woman to the ground and covered her mouth with his hands as she screamed, police said.He couldn't stop her from screaming so he stood up, touched her in a sexual manner and then fled on his skateboard.A family leaving their home near the scene heard the woman's screams and came to help her."As we were approaching our vehicle, a woman came running and screaming that she had been attacked and that she needed help," Theresa Hightower said. "You could see that there had been some kind of scuffle, attack ... she was fighting and she said he grabbed her private area."Hightower said the victim pointed to where the attacker had fled. Hightower's husband drove around searching for the suspect but could not find him.Police said they are increasing patrols in the area and working to identify the suspect.Investigators describe the suspect as a man in his early 20s; 5 feet, 10 inches to 6 feet tall; thin or medium build. He was wearing a black hooded sweatshirt and dark pants and riding a skateboard.Police asked residents who may have surveillance footage from the area during those times to contact them. They are also looking for video from homes that face the Jeffrey Open Space trail.Anyone with information or video should contact Detective Keith Herter at 949-724-7183 or kherter@cityofirvine.org.