Palo Alto police are investigating two prowling incidents that they say occurred on Sunday night in residential neighborhoods around California Avenue, including a case in which a stranger was caught trying to look through closed blinds into a woman's bedroom.

Police first learned about the prowler at 8:42 p.m., when a caller reported seeing a suspicious person in the 2300 block of Yale Street, near Cambridge Avenue. The caller, a woman in her 50s, reported that at about 8:20 p.m., a man approached her as she was unloading items from her car and began to make small talk, police said in a news release. After a brief chat, the woman began feeling like the man was trying to come on to her, police said. She ended the conversation and then walked away, police said.

About 20 minutes after the initial encounter, the victim reportedly heard the doorknob on her locked front door shaking, as if someone was trying to get inside the house, police said. She also heard the doorbell ring and when she went to answer it, she saw the back of a man walking away. Police said she asked him what he wanted, but he ignored her and walked away south on Yale Street.

She called the police but responding officers could not locate the man.

Later that evening, police received another report of a suspicious person in Evergreen Park, the neighborhood next to College Terrace and across El Camino Real. At 11:12 p.m., a woman in her 20s, reported that she had just returned home when she saw a man standing in the bushes of her side yard in the 200 block of College Avenue. She said the man was trying to look through the closed blinds into the bedroom window of her roommate, also a woman in her 20s, police said. The woman reportedly asked the man if she could help him, but he immediately walked away, police said.

The woman then called the police, who arrived but could not find the man, according to the news release.

Police said the women in both cases had simliar descriptions of the suspect: a clean-shaven white man in mid-40s to mid-50s, 5 feet 9 inches to 6 feet tall and with a medium build. He was reported as having short brown hair that may be graying, blue jeans and either a short-sleeved blue T-shirt or a red plaid shirt. Investigators released a sketch of the suspect on Thursday afternoon.

Palo Alto detectives are also exploring whether the man in these two cases is connected to a separate prowling incident that occurred on March 21 in the 1100 block of Emerson Street, near Lincoln Avenue. In that incident, a woman in her 70s called the police after spotting a man in her backyard, looking into her home. Police said the man ran away after she yelled at him and officers who responded could not find him.

Since then, detectives had identified a possible suspect in the Emerson Street incident and have sent the case to the Santa Clara County District Attorney's Office for review, though no decision about the charges has been made as of Monday, police said.

Police encourage the public to promptly report suspicious behavior by calling the dispatch center at 650-329-2413 or, if it's an emergency, 911. Anyone with information about this incident is asked to call the dispatch center. Anonymous tips can be emailed to email paloalto@tipnow.org or sent by text message or voice mail to 650-383-8984. Tips can also be submitted anonymously through the Police Department's free mobile app, downloadable at bit.ly/PAPD-AppStore or bit.ly/PAPD-GooglePlay.