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$5,000 reward offered in series of 'unprovoked, random assaults' in Massachusetts

Authorities in the city of Waltham are “dramatically increasing” patrol in search of a suspect believed to be linked to 10 unprovoked attacks since Nov. 10.

Authorities in Massachusetts offered a $5,000 reward in its search for a suspect who is believed to be responsible for a series of at least 10 “unprovoked, random assaults” in the city of Waltham.

Police in the city of Waltham, about 12 miles west of downtown Boston, said Tuesday that the city was “dramatically increasing” its search for information leading to the arrest and conviction of the suspect, including drone surveillance and increased patrol presence, NBC Boston reported.

Waltham Police Chief Keith MacPherson said Tuesday the suspect appeared to be "lying in wait" for men, according to NBC Boston. The suspect would then attack them from behind without warning by striking their heads, sometimes with objects.

Lead detective Sgt. Steve McCarthy said it was an “awful situation,” the station reported. The department did not immediately respond to an NBC News request for additional details.

“There is definitely a fear factor in our city right now. We’ve never experienced anything like this,” McCarthy said during the Tuesday news conference. “I'd be lying to you if I said I'm not losing sleep at night, you know, coming into work.”

Last week, the Waltham Police Department released surveillance footage of a man who they said carried out five assaults near an apartment complex between Nov. 10 and Nov. 20.

Police believe the same man is responsible for nearly a dozen random violent assaults in which men were attacked and sometimes struck in the face or head with an object.Waltham Police Department

The series of attacks occurred between 5:30 p.m. and 11:30 p.m., police said. The city has since reported another five who were assaulted in downtown Waltham, NBC Boston reported.

In the surveillance video, the suspect can be seen running and walking. Investigators did not release any additional surveillance footage during the Tuesday press conference nor have they determined a motive.

"The motive is somewhat in question, but it appears to be the thrill of the assault, as someone who's very violent and enjoys seeing someone hurt by this," MacPherson said Tuesday.

The most recent attack occurred on Friday, NBC Boston reported. The victim, Emerson Aroche Paz, told the station he was struck in the face by a blunt object on his way home on Wednesday evening.

Paz, 41, told the station that his nose and a few bones encircling his left eye were broken by the assailant, who wore a green jacket, a hood, and a ski mask — matching the description of previous victims, according to the affiliate.

Officers in Waltham urged residents to be aware of their surroundings, particularly at night.