He followed his father, a veteran of Vietnam, into the Army, and spent a year fighting in Iraq. Arlester Jay returned home addicted to drugs and alcohol, his father said, and he was diagnosed with post-traumatic stress disorder. He was homeless for a time, unable to hold even a menial job.

D.C. police pulled Jay’s body from the Anacostia River on Monday after a rower spotted it floating near the Langston Golf Course in Northeast. The discovery ended a nearly four-week search after Jay’s family reported him missing in early March.

For Jay’s father, the gruesome discovery brought one small part of sad relief over a life that had spiraled out of control into petty crime and substance abuse. But it was much more a moment to vent years of pent-up anger at the way he believes veterans are treated after they come home from war.

“That boy gave his all for his country,” said Ernest Jay Jr., a 71-year-old Methodist minister, just hours after learning of his son’s death Tuesday. “And they did nothing.”

Ernest Jay said his son did not talk much about what happened in Iraq, but he knew it was traumatic. One on occasion, his son told him of having to pull dead friends from a vehicle that had overturned in a river.

Back home, Arlester Jay, who was 36 when he died, sometimes refused to follow his treatment regimen from the Veterans Affairs Department. But the doctors gave up on him, his father said. “It’s a godless, immoral country,” he said.

Jay said he believes his son was murdered. On March 10, Arlester Jay’s sister, Meredyth Jay, went to her brother’s apartment in Forestville to help his recently estranged girlfriend move out. But she said Arlester Jay was not there. His cellphone went to voice mail, and his car was gone. Prince George’s County police said they took a missing person report on March 14.

D.C. police detectives are awaiting results of an autopsy to determine how Jay died, but the homicide squad is already involved.

“He was a good person,” Ernest Jay said, noting that his son was diagnosed with PTSD and received disability checks. He has four surviving brothers and three sisters. Two sisters and his mother died previously. “He was sick, ” his father said, “and strung out on drugs. It’s a tragedy.”

The Army confirmed that the younger Jay was a unit supply specialist from May 2002 to March 2005, assigned to Fort Lewis in Washington state. He deployed to Iraq — and heavy fighting in Fallujah, his father said — in October 2003; he left a year later. Authorities said his awards included the Army Commendation Medal, National Defense Service Medal and Global War on Terrorism Service Medal.

Ernest Jay said his son came home and became despondent, hiding in his room when high or drunk, and failing to hold down clerk jobs at stores. He has a long list of arrests in Maryland and Virginia, mostly involving alcohol and drunk driving but a few suggesting minor violence.

One of his few convictions came from his only arrest in the District, in April 2007, when an police officer spotted him drinking from a 24-ounce silver can of Steele Reserve lager while sitting on a park bench at Fourth and and H streets Northwest, near the Government Accountability Office.

That began an odyssey through the courts, during which the prosecutors dropped the charges but convicted him of repeatedly failing to appear for court, resulting in his eventual arrest at a sister’s house in Harrisonburg, Va., in 2009. He was ordered to serve a 90-day sentence, but with 10 days left, his father appealed to a D.C. Superior Court judge to let him out to attend his mother’s funeral.

In his letter to the court, Ernest Jay described his son’s plunge into drugs, his initial refusal to get treatment, and his change of heart and multiple failed attempts to get well at a VA medical center in West Virginia. Sometimes he refused to cooperate or was scared to take medication. Once, while he was waiting for an inpatient treatment bed at another facility, he reverted to getting high before space opened up.

“Arlester was always a good son,” the father wrote the judge. “He joined the U.S. Army and unfortunately was sent to Iraq where he witnessed many traumatic events of killings and losing fellow soldiers, including a young gal with whom he was in love.”

The judge let him out for the funeral of his mother, Joyce Jay, then 66, in Upper Marlboro.

A few years ago, Jay moved out of his father’s house in Laurel because he wanted to be on his own. He lived in the District and then moved with his girlfriend to an apartment in Prince George’s County. They broke up in an argument over money; she did not work, his sister said, and he could not afford to support both her and himself on his disability payments.

On March 10, Meredyth texted her brother and said she was coming the next day to help his ex-girlfriend move. He texted back, “OK.” It was the last time the two communicated.

Jennifer Jenkins contributed to this report.