After his car veered off Oregon 6, struck a utility pole and rolled to a stop against a tree, the driver ended up at Tillamook Hospital.

State police who responded to the crash site found the ground littered with objects that had spilled out of the car: a glass meth pipe, pill bottles, metal spoons with heroin residue. Inside the car, the trooper could see a rifle case and magazines of ammunition, according to police and prosecutors.

The trooper removed an AR-15 rifle for safe-keeping and interviewed the driver at the hospital. He admitted the drug paraphernalia was his and that he last used drugs the day before. The crash occurred when he swerved to avoid an animal in the road, he said.

The driver also gave his name as Jeffrey Mercer.

But that was a lie that set off a series of mistakes and ultimately sent the driver to federal prison for almost four years.

At the hospital, the trooper cited the man for careless driving and possession of heroin and methamphetamine. The trooper said the driver passed sobriety tests and didn’t appear to be impaired.

The trooper also returned the AR-15-style assault rifle to the driver.

A month later, the real Jeffrey Mercer called state police. He wanted to know why he had a warrant for his arrest for failure to appear in court. He said he’d never been in an accident in Tillamook County.

The real Jeffrey Mercer told police they had the wrong guy and might be looking for his brother, Richard Mercer.

Richard Mercer, 39, has a lengthy criminal record and often used his brother’s name during contacts with police, according to police and prosecutors.

On Tuesday, Richard Mercer was sentenced in federal court in Portland for being a felon in possession of a gun on Sept. 20, 2017, the day of his crash.

“Not only does he lie and give a false name but he implicates his brother,’’ Assistant U.S. Attorney Gary Sussman told a judge. “To this day, we have no idea where his assault rifle is. … His lies caused this firearm to be given back to a six-time convicted felon.’’

At the time he was initially cited, Richard Mercer didn’t present the trooper with any ID, Sussman said. The trooper apparently took him at his word, the prosecutor said.

State police ultimately identified Richard Mercer as the man who had crashed his car, partly by recognizing a tattoo of a heart on his chest from a photo that matched the one the trooper recalled seeing at the hospital.

Richard Mercer has 18 prior convictions, including six felonies, and 15 probation or supervision violations.

Less than two months before the crash, he was convicted of being a felon in possession of a restricted weapon and was sentenced to 22 days in jail and a year and a half of probation. Four months after the crash, he was convicted in Multnomah County of reckless driving and possessing a loaded firearm in a public place.

Richard Mercer had prior convictions for delivery of heroin in Deschutes County in 2015, burglary and criminal mischief in Salt Lake City in 2008, first-degree theft in Washington County in 2005.

“He is a serial recidivist offender,’’ Sussman argued, pushing for a sentence of four years and nine months.

Defense lawyer Celia Howes asked for a sentence of two years and six months, saying her client acknowledges that he has a “disastrous’’ criminal history but now wants to get his life together as the father of 1-year-old twins. He realizes he’s lost the trust of his brother and mother, she said.

His crimes were fueled by methamphetamine and heroin addiction, which helped numb the pain of childhood abuse, she said. While in custody, he’s taken advantage of a “Life Lessons’’ program, a 12-step program and parenting classes.

“There’s no feeling but shame, regret and accountability for that long, troubled criminal history,” Howes said.

Richard Mercer, standing before U.S. District Judge Michael H. Simon in a striped black-and-white jail suit, said he recognized that his crimes as a “drug-addicted, dishonest, manipulative person’’ have left a “trail of wreckage.’’

But he said the birth of his children made him realize for the first time how his actions affect others and that he’s committed to staying sober.

His lawyer urged the lower sentence, noting this is the first federal conviction for Richard Mercer. Howes said that even a 30-month sentence will be the longest prison term her client has faced.

“It’s about time,’’ Sussman responded, “because nothing else has stopped him.’’

The judge issued a sentence of three years and nine months.

Simon said he considered Richard Mercer’s obstruction of justice and his possession of an assault rifle that he had no legal authority to have and still hasn’t turned in to authorities.

-- Maxine Bernstein

Email at mbernstein@oregonian.com

Follow on Twitter @maxoregonian

Visit subscription.oregonlive.com/newsletters to get Oregonian/OregonLive journalism delivered to your email inbox.