Five armed home invasions have been reported in Suffolk County in a week—two on Sunday alone—but despite eight arrests, three of the cases are so far unsolved, authorities said.

None of the incidents appear to be random and the victims in some cases knew their attackers, authorities said. The incidents occurred in Mastic, North Lindenhurst, Dix Hills, Huntington and Coram between Jan. 15 and Jan. 22. Five were nabbed in the Huntington case and three were busted for the North Lindenhurst case.

The first case came when police said a Mastic woman reported a pair of masked gunmen broke into her Wills Avenue home, stole her iPhone and fled at 2:30 a.m. Tuesday, Jan. 15. The victim reported that one assailant was wearing a Spiderman mask.

Then at 10:30 p.m. Sunday, three Brentwood men—one armed with a handgun—forced their way into a North Lindenhurst home on Feustal Street, where they stole cash and cell phones from the victims inside. The trio was arrested shortly afterward.

A half hour later, two masked gunmen walked into a Dix Hills house on Deer Park Avenue through an unlocked door, pistol-whipped a man and woman inside and fled with the victims’ wallets and cell phones, police said.

“They appear to be targeted locations,” Second Squad Det. Sgt. Richard Auspaker said of the Dix Hills case and the arrest of five men for an alleged home invasion in nearby Huntington two days later. “It’s possibly related.”

In the Huntington case, police said three suspects entered a home on Leigh Street through an unlocked door, threatened five residents inside and demanded cash while the other two suspects acted as lookouts outside at 1:20 a.m. Tuesday.

All five men fled in a Lincoln but were apprehended shortly later on Deer Park Avenue in Dix Hills, police said. Two guns were allegedly recovered.

And in the fifth case in the eight-day span, police said four men forced their way into a Coram home on Townhouse Road, one suspect displayed a rifle and the group tied up a woman and three children at 9:30 p.m. Monday. It’s unclear what the suspects stole.

The victims in the Dix Hills case were treated for minor injuries at Huntington Hospital. The victims in the other four cases were not injured.

No arrests have been made in the Mastic, Coram or Dix Hills cases. A police spokeswoman said the Mastic and Coram cases were also believed to be targeted.

“It doesn’t appear that these two are related to other precincts,” Auspaker said of the Huntington and Dix Hills home invasions versus the other three.

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