The early-morning attack by an intruder who broke into a Palo Alto woman's apartment may be linked to other incidents in the recent months, Palo Alto police said Thursday.

The male suspect forced open the front door of the apartment in the 100 block of Hawthorne Avenue around 2:20 a.m., police said.

The victim, a Stanford grad student in her 20s, was asleep in her bedroom when the suspect made entry.

The woman screamed when she realized someone was in her bedroom, and after a brief struggle, the intruder fled on foot. The woman suffered a bruised wrist, but was otherwise uninjured, police said.

The victim never got a good look at the suspect's face.

Police said it appears the intruder intended to sexually assault the resident, according to police.

The woman called 911, and officers began a search for the suspect with a K-9 unit from the Mountain View Police Department.

The suspect was only described as a male with an average build wearing a dark hooded jacket or sweatshirt and dark pants, according to police.

Palo Alto Police expressed concern that Thursday's attack might not have been an isolated incident. Authorities are looking at past crimes including three prior groping cases in August and September.

All the attacks happened near the site of Thursday's incident, including one a little more than a block away.

"We're going to look at the locations where they occurred," Palo Alto Police Sgt. Brian Philip. "We're going to look at the possible suspect descriptions on those [assaults]. We're going to look at the victims in those cases to see if they relate to the case we have today."

If the crimes are linked, authorities said they appear to be escalating.

Investigators are now trying to determine if the woman might have been followed home.

Neighbors said they'll be extra cautious until the man is caught.

"And I've heard it happen in this area, 'cause I've been here a few years now. A handful of times, so it was really jarring," said neighbor Jonathan Ngyuen.

"I'm usually very careful. I never go out by myself at night like at 2 a.m. or 3 a.m., said Palo Alto resident Elaine Tsai. "It does kind of make me take a second glance when I'm out, even in the daytime, because you just can't take anything for granted."

Anyone with information about the case is asked to call the Palo Alto Police Department's 24-hour dispatch center at (650) 329-2413. Anonymous tips can be e-mailed to paloalto@tipnow.org or sent via text message or voicemail to (650) 383-8984.