Drug dealer's conviction is justice for family of Selden man who overdosed on fentanyl

The last time Fredrick Koenig’s family saw him alive was on Christmas night 2018, as he stayed up past 2 a.m. doing dishes and cleaning up from what was also his mother's birthday celebration, his parents recalled Tuesday.

The next morning the Selden man was found dead inside his parents’ home, another victim of Long Island’s battle with opioid addiction.

So on Tuesday, when the man who sold their 36-year-old son the fatal dose of fentanyl was convicted in federal court, the Koenigs felt justice had been done.

A jury convicted Marlon Thompson, 41, of Selden of conspiracy to distribute fentanyl, heroin and cocaine base and distribution of a controlled substance causing the death of Koenig after a six-day trial before United States District Court Judge Joan Azrack at Eastern District Court in Central Islip. Thompson faces 20 years to life in a federal prison when he is sentenced May 11.

“We’re feeling a lot of justice and Long Island is getting a lot of justice for all the drug deals that went away on this case,” dad Frederick Koenig told Newsday.

U.S. Attorney Breon Peace said Thompson was responsible for drug sales across Suffolk County and prosecutors said he continued to sell the drugs for several months after Koenig’s death. Law enforcement recovered fentanyl and drug packaging materials from Thompson’s bedroom during the investigation and also seized three illegal guns and ammunition from a storage unit he rented, the U.S. Attorney’s Office said in a news release.

“The large quantities of fentanyl [Thompson] distributed all over Suffolk County had a devastating impact on the community, including by taking this young man away from his family too soon,” Peace said in a statement.

Koenig described his son as a “great person, a family man.” A union electrician, he had three siblings, including twin sister Mellisa, and doted over his niece and five nephews, his father said. 

Denise Koenig, Fredrick's mom, was among those who testified for the jury, describing how she found her son's lifeless body as prosecutors also played her 911 call.

The Koenigs attended each day of the trial. "We're very pleased with the outcome after a long process that took even longer because of COVID," Denise Koenig said.

The government’s evidence against Thompson included testimony from co-conspirators, text messages between Thompson and other alleged drug dealers discussing deals, drug paraphernalia and thousands of dollars of bundled U.S. currency seized from his residence, according to a news release. The investigation revealed Thompson was involved in drug sales for more than two years from January 2017 through May 2019. 

“This case is a stark reminder of the tragic devastation that the opioid epidemic has inflicted regionally, and specifically upon Suffolk County,” District Attorney Ray Tierney said in a statement.

By Grant Parpan

grant.parpan@newsday.com@GrantParpan

Grant Parpan covers Suffolk County courts and federal courts for Newsday. A Long Island native, he joined Newsday in 2022.