SAN DIEGO -- A 28-year-old Los Angeles police officer accused of selling methamphetamine in San Diego and Riverside counties is due to appear before a federal magistrate in downtown San Diego Thursday.

Yoshio Romero -- a five-year veteran of the LAPD -- was arrested at his Corona home on Monday by Drug Enforcement Administration agents. He made his initial court appearance before a Riverside federal judge on a single count of distribution of methamphetamine the next day.

The offense carries a minimum of 10 years in federal prison, according to prosecutors.

Romero's arrest followed a months-long investigation stemming from his alleged sale of $4,200 of meth, according to the U.S. Attorney's Office.

On Dec. 1, 2009, Romero, identified in court papers as "Socho," was contacted by an undercover agent about purchasing meth, according to a DEA affidavit filed in support of the criminal complaint.

The defendant allegedly told the agent that he "could supply him with any quantity of methamphetamine that he wanted," according to the affidavit.

The two arranged to meet at a shopping mall in Temecula two weeks later, and during the meeting, Romero gave the agent a "small baggie containing a small amount of a white crystalline substance, which he (called) a 'free sample,'" court papers allege.

Tests verified the substance was meth, according to the DEA.

Afterward, the undercover agent arranged to make a larger purchase, which Romero allegedly agreed to do at the North County Fair in Escondido on Dec. 21.

The defendant left 114 grams of high-grade meth in a candy box in his blue Chevrolet S-10 pickup truck, the affidavit alleges.

The undercover agent was instructed to retrieve the drugs, leave the $4,200 cash payment in the center console and lock the doors of the truck after the transaction was finished, according to the affidavit.

"A few minutes later, Romero was observed going to the ... pickup, using a key to gain entry and then driving off," the affidavit states.

According to an LAPD statement, federal agents notified the department in April of Romero's suspected involvement in off-duty meth sales.

The LAPD said it initiated an internal probe and cooperated fully with federal authorities in their investigation.