RUMFORD – Citing insufficient evidence Wednesday, the Oxford County District Attorney’s Office dismissed felony charges against a Rumford man accused of detonating a bomb in his neighborhood.

The acid bomb exploded early Sunday morning in a snowbank outside the Cumberland Street apartment building where Michael Shane Rowe, 24, lives, police said. It detonated beside a Rumford patrolman’s cruiser as he drove up to assist two fellow officers investigating an underage drinking complaint.

Because the officers assumed they were under rifle fire, police were massed at the site. Later, Rowe was arrested on charges of criminal use of explosives, reckless conduct with a dangerous weapon and furnishing a place for minors to consume alcohol.

He was also arrested on a Lewiston District Court warrant charging operating after suspension.

Rowe, who had been held on $50,000 cash bail in Oxford County Jail in Paris since Sunday, had his charges dropped Wednesday morning by Assistant District Attorney Joseph O’Connor.

“There was not sufficient evidence to charge him at this time,” O’Connor said by phone late Wednesday afternoon in Paris. The complaint was dismissed and the charges dropped.

However, due to the warrant, an Oxford County Jail official said Wednesday that Rowe was taken to Androscoggin County Jail in Auburn to await arraignment in Lewiston District Court. Bail on the warrant was $240 cash.

An official at the Auburn jail said late Wednesday afternoon that Rowe wasn’t incarcerated there. The Lewiston court couldn’t be contacted because it was after hours.

Rumford police Detective Lt. Mark Cayer said Wednesday afternoon that he was surprised O’Connor dropped the charges.

“We will continue to gather evidence and statements and present it to the (Oxford County) grand jury,” which meets next month, Cayer said.

Shortly after 1 a.m. Sunday, Officers Paul Casey and Jennifer Kramer were climbing stairs to Rowe’s apartment at the same time Officer Eric Lippincott was driving in.

About 10 or 15 minutes prior, Cayer said Rowe had made an acid bomb and thrown it into a snowbank, but the device failed to explode.

“I don’t believe there was any intent to harm officers,” Cayer said.

An acid bomb is created by combining a mixture of chemicals inside a container. Detonation happens after the resultant gas builds pressure to the point of exploding, Cayer said.

“That’s why those devices are so unsafe. You can’t tell what they will do. It depends on the mixture of the solution. Rowe didn’t say why he made the bomb … I think his intent was to throw it outside, and there was a time delay. You wouldn’t want one of those things going off inside your house. They’re truly dangerous. It fell three stories, hit a snowbank and got buried. I think that protected the officers from the percussion,” Cayer said.

When the explosion reverberated around the neighborhood, the lights in Rowe’s third-floor apartment went out. Casey and Kramer broke into an apartment seeking cover, while Lippincott reversed direction and secured the street.

“Casey, Kramer and Lippincott did exactly what they should have done. They’re thinking that someone was up there with a firearm. Paul said it sounded just like a rifle,” Cayer said.

After the tactical squad and additional police arrived, Cayer said he phoned Rowe and four others in the apartment, apprised them of the situation and ordered them outside one at a time. They complied.

“I wouldn’t call it a standoff. Once we made contact and they realized we were there for them, they came out … We handled it like a standoff because there were too many civilians in apartments around there,” Cayer said.