PORTLAND, Maine — A boater accused of causing a fatal collision was either “obscenely reckless” in drinking and speeding across a lake at night or a conscientious boater who didn’t foresee encountering another vessel that was “essentially invisible” because it lacked proper lights, jurors were told Monday.

Prosecutors and the defense painted two vastly different pictures of Robert LaPointe’s actions during closing arguments in his two-week manslaughter trial.

District Attorney Stephanie Anderson said LaPointe had a beer in his hand all day before the crash and was drunk when his 32-foot speedboat No Patience — traveling at upward of 65 mph — ran over a smaller boat in its path, killing two people on Long Lake in Harrison.

“Can there be any conclusion other than that the defendant was reckless — obscenely reckless?” Anderson asked jurors in Cumberland County Superior Court.

Defense lawyer George Hassett countered that LaPointe was not impaired and that the collision wouldn’t have happened if the smaller boat had proper lighting. A staged recreation showed the smaller boat would have been “almost entirely invisible” or “essentially invisible” to LaPointe’s oncoming boat, he said.

Jurors deliberated about four hours before breaking for the day without a verdict. They were to resume their deliberations Tuesday morning.

Killed in the collision on night of Aug. 11, 2007, were Terry Raye Trott, 55, of Harrison, and Suzanne Groetzinger, 44, of Berwick. LaPointe, 39, of Medway, Mass., and his passenger survived being thrown from their boat, which sped across the lake and came to rest 100 feet in the woods.

LaPointe is charged with two counts of manslaughter, two counts of aggravated operating under the influence and reckless conduct with a dangerous weapon.

On Monday, Hassett sought to cast doubt on a blood test showing LaPointe’s blood-alcohol level was 0.11 percent three hours after the crash by reiterating that it was left in a warden’s truck for more than 30 hours before arriving at a lab. No witnesses testified that LaPointe appeared to be drunk, he noted.

But Anderson said the blood-alcohol test was not compromised by its handling, and she said LaPointe’s blood-alcohol content was probably higher at the time of the crash.

Referring to the operating-under-the-influence charge, she said, “We don’t have to prove that he was slurring, or staggering, or falling down drunk. We only have to show that he was over 0.08 percent.” The legal limit for operating a boat in Maine is 0.08 percent.

Jurors will have to sort through plenty of conflicting testimony, including whether or not Trott’s 14-foot motorboat had its lights on.

Some witnesses testified that the boat had no lights, but others said there were lights. An expert witness testified that the “all-around light” that serves as a beacon at night was likely not operating even though the boat’s light switch was discovered to be in the “on” position.

Anderson said that even if the smaller boat lacked proper lighting, LaPointe had seen the boat depart the dock and knew it was out there on the lake.

“He can rant and rave all he wants [about the lighting on the boat] but what he cannot do is say he didn’t know the boat was out there,” she said.

The speed of LaPointe’s boat also was in dispute.

LaPointe testified Friday that he was operating at 30 mph and that he felt pressured by a warden into saying in a recorded interview that he was traveling at “maybe 40, maybe 45.” Witnesses said the boat was operating at 50 mph, and an expert said it could have been going between 50 and 65 mph.

Finally, there was the issue of drinking.

LaPointe testified he drank only three beers on the day of the crash despite telling a nurse that he’d been drinking all day, then stopped for an hour and consumed another three to six beers before getting in the boat. Hassett pointed out that no one ever performed a field sobriety test on LaPointe.

The nurse testified that LaPointe gestured to her that he wanted her to take her own blood sample to substitute for his. LaPointe, who didn’t want to give a blood sample, testified he was merely seeking her advice about what she’d do under the circumstances.