Portland police have arrested five men, and are searching for another, on a series of assault charges after a deadly shooting this summer that prosecutors said stemmed from a dispute between two motorcycle clubs.

The arrests come months after Aaron Karp was charged with murder in the death of  54-year-old Susan McHugh of Gray. He has pleaded not guilty and is being held without bail at the Cumberland County Jail.

The five men charged this week with elevated aggravated assault and conspiracy to commit assault are: Kaleb Cidre, 22, of Windham; Jason Keenan, 45, of Bath; James Moody, 30, of Bowdoin; Caleb Pelkey, 33, of Portland; and Nathan Walsh, 48, of Lewiston.

Police are still trying to find a sixth man, 45-year-old Kristofer Haken of Londonderry, New Hampshire. Portland police said that Haken is considered “dangerous and may be armed” and that they believe he is linked with the Outlaws Motorcycle Club.

Karp, who was arrested in August, also has ties to the biker club, according to investigators. In previous court hearings, a prosecutor for the state said that the entire incident stemmed from rivalries between the Outlaws and another club.

An affidavit for Karp’s arrest is still not publicly available.

It’s unclear what roles police believed the five men charged played that night. Spokesperson Brad Nadeau declined to share any information on whether police believe the men are connected with either motorcycle club.

At a bail hearing in September, Portland Police Detective Jeffrey Tully testified that he saw surveillance camera footage of Karp firing a gun at McHugh the night of July 30.

Hours earlier, McHugh’s son, her husband and their friend (all of whom are members of the rival motorcycle club FSU) got into an argument at a restaurant in Westbrook with members of Higher Calling, which is affiliated with the Outlaws. The argument was caught on the restaurant surveillance camera, the detective said.

As the FSU members left the restaurant, the detective said, the Higher Calling members appeared to be making several phone calls.

Around 8:45 p.m. that night, the McHughs were parked in a lot near Samuel’s Bar & Grill. When Karp and others arrived, the group began attacking the McHughs with two-pound mini-sledgehammers and a wrench, the detective said. At least some of the men who arrived to the parking lot with Karp were among the five who were recently arrested, according to names Tully shared during the hearing in September.

Susan McHugh was crouched behind their car, firing her husband’s gun at Karp’s group. As Karp and his members fled, he tripped, and police said the video showed him firing nine rounds in Susan McHugh’s direction.

Troy McHugh and Holmes were taken to the hospital with fractured skulls.

Their first appearances in court were not yet scheduled as of Wednesday morning.