A man who's sold pet pharmaceuticals online illegally since 2002 reached a deal last week with U.S. government prosecutors.

Sean Lawrence Gerson, 49, will plead guilty to illegally importing and fraudulently selling misbranded pet prescription drugs, and the marketing of unregistered pesticides, per an agreement filed Sept. 7 with the U.S. District Court for the Central District of California.

The offenses to which Gerson will plead guilty carry a maximum 24 years in prison with three years of supervised release, a $600,000 fine and a special mandatory assessment of $225.

If the agreement is accepted by the court, Gerson will be sent to prison for 30 months followed by three years of supervised release. The deal also requires Gerson to forfeit $2.5 million in assets and pay a $200,000 fine. Sentencing is set for December in front of Judge R. Gary Klausner, according to Jeffrey Kent, Gerson's attorney.

Signed by Gerson on Sept. 3, the plea deal signals the end of a six-year federal investigation into his involvement in multiple websites that sell veterinary drugs illicitly. Gerson was arrested in December. Trial originally was set for March 7 and postponed until Sept. 19. In May, the government convened a reverse proffer meeting designed to induce a settlement by unveiling the prosecution's case.

Any time that Gerson already has spent in custody will not be credited to his sentence. However, prosecutors suggest that the sentence run concurrently with any potential prison time Gerson might receive for violating probation related to a felony conviction in Texas in 2014 for the illegal sale of clenbuterol, a bronchodilator that improves horses' breathing.

The agreement precludes further criminal prosecution that may arise from Gerson's conduct as outlined in the filing, "including violations of the Federal Insecticide, Fungicide, and Rodenticide Act, counterfeiting, smuggling and customs transgressions, and conspiracy."

In exchange, Gerson concedes the following:

• He began importing foreign-branded, unapproved and misbranded prescription animal drugs and selling unregistered pesticides in 2002 through his company Vaccination Services Inc., based in Lake Forest, California.
• He knowingly dispensed prescription animal drugs without the lawful order of a licensed veterinarian, acting with intent to defraud or mislead the U.S. Food and Drug Administration.
• In June 2012, he sold unregistered and foreign-branded flea and tick products to an undercover law enforcement officer in Washington state.
• In August 2016, Gerson and Vaccination Services sold foreign-branded ciprofloxacin and Comfortis without a veterinarian's prescription to an undercover law enforcement officer in Missouri.
• Between 2002 and 2017, Vaccination Services amassed at least $2.5 million in proceeds from the fraudulent receipt, purchase, concealment, sale or transportation of illegal pet drugs and parasiticides. (The plea deal does not shield Gerson from prosecution for any criminal tax violations.)
• He was an organizer or leader of the criminal activities, which included five or more participants.

The agreement does not identify any alleged colluders. Previous court documents name Lam Tran and Chris Martin, both indicted defendants in another case involving pet medications, as Gerson informants.