The University of Massachusetts Police Department arrested Christopher Williams on two counts of open and gross lewdness, according to a crime alert sent to the campus community Thursday evening.

Williams is the suspect in two separate incidents that took place last week.

On Aug. 20, a female victim reported a man calling her over to his vehicle, a gold Honda Civic, according to a crime alert sent out last week. Upon approaching the vehicle, she observed him masturbating.

According to a second crime alert, the next day another female victim reported a gold Honda pulling up next to her with the driver masturbating inside, making no attempt to conceal his activity.

Both instances occurred midday in Lot 25 on campus.

In the email alert, UMPD Chief John Horvath said, “Officers had very limited information at the outset of this investigation and only after their exhaustive work were they able to zero in and identify this person. It was critical that we moved swiftly and remained diligent in this case to prevent a continuation of the activity or an escalation of his behavior.”

The arrest was made with the assistance of the Greenfield Police Department, and Williams was arraigned in Greenfield District Court Thursday.

Marie MacCune can be reached at [email protected] and followed on Twitter @MarieMacCune.