For the third time this week, a man in a car allegedly pulled up next to a female passerby and lewdly exposed himself on a Palo Alto street.

In the latest incident, the victim was a woman in her 20s who was biking on Thursday evening at around 3:30 p.m. on the 4300 block of Miller Avenue, near the Mountain View border, police said. She reported that she had been riding her bicycle north, from Mountain View, when she saw a BMW drive by her and then stop in the middle of a traffic lane ahead. She said she slowed down to pass the car on the right when the driver called out to her. When she stopped and looked in the car, he was exposing himself and masturbating, police said.

She reported that she immediately crossed the bike bridge leading to Wilkie Way and last saw the BMW turning west on Monroe Drive. She called police about 30 minutes later.

The victim described the flasher as clean-cut and "professional looking," police said. He was wearing a yellow button-down Oxford-style shirt and was wearing "sporty" Oakley-style sunglasses. She said the BMW was a four-door sedan which looked clean and relatively new.

Police are unsure whether the man involved in Thursday's flashing is the same one who drove a truck and masturbated in front a 14-year-old girl who was walking her dog on Bryant Street on Monday. The day after the Bryant Street incident, a man in a white Volvo reportedly pulled up next to a 10-year-old girl on Byron Street, exposed himself and asked her if she wanted to touch him. While those two incidents occurred within half a mile of each other, Thursday's took place about three miles away, near the city's southern edge.

In response to these incidents, police said they have increased marked and unmarked patrols, paying particular attention to popular school-commute routes. The Police Department is also increasing surveillance. In a statement, police said that they have brought in additional staffing and re-assigned personnel to work on these cases.

The public is asked to report any suspicious activity immediately by calling 9-1-1. Police are also urging residents to be aware of their surroundings and advise parents "to tell children to be alert and to tell a trusted adult immediately about anything they see that does not seem quite right."