Days before he was to go on trial in New London Superior Court, Antonio “Wilson” Peña pleaded guilty to arranging the murder of a rival who has since been locked up on federal drug-dealing charges.

A jury had been selected and evidence was to start Monday, but the state reopened plea negotiations because the intended victim, Oscar “Tato” Valentin, is in federal custody, according to prosecutor Christa L. Baker.

Valentin was one of about 100 people arrested last month in a massive drug raid in southeastern Connecticut. Federal officials said Valentin received wholesale quantities of cocaine from Puerto Rico and distributed the drugs from an 11-bay garage he managed at the intersection of Bristol and Walker streets in New London. He remains in federal custody.

Peña, 36, pleaded guilty Thursday to conspiracy to commit murder and will be sentenced July 18 to eight years in prison followed by six years of special parole. The state had previously offered a 14-year prison sentence.

Peña pleaded guilty under the Alford Doctrine, which indicates he does not agree with the state’s allegations but does not want to risk conviction at trial and the possibility of a lengthier prison sentence.

His father, a minister from Puerto Rico, had traveled to New London to see that his son’s case was resolved, according to defense attorney William T. Gerace. With the help of a Spanish interpreter, Judge Susan B. Handy explained the procedure to the father and son.

According to New London police, Peña was upset that Valentin had taken his drug-dealing business. Police said that in August 2011, he planned to pay $5,000 to Gerardo Carrillo, 26, of 64 Fawn Hill Drive, Westbrook, and $10,000 to Elmer A. Melendez, 28, of 208 Crystal Ave. Tipped off by an informant, police pulled over the informant, Carrillo and Melendez after the informant and Carrillo picked up Melendez at his apartment.

Baker, the prosecutor, said Thursday that Peña, who was in drug rehabilitation, wanted the men to slit Valentin’s throat before Peña was released from the program. Police recovered a knife and a 9 mm handgun from the men.

Melendez and Carrillo were charged with conspiracy to commit murder and remain incarcerated. Their cases have been on hold pending the outcome of Peña’s case.

While Peña was incarcerated, his wife’s brother, 36-year-old Javier Reyes, was stabbed multiple times at the family’s Huntington Street apartment on Sept. 12. The police and state’s attorney’s office have not confirmed whether Reyes’ stabbing death and the murder-for-hire plot are connected. In November 2012, Peña offered, through his attorney, to meet with a state’s attorney to review video surveillance taken at the apartment complex on the night Reyes was killed. The police investigation is continuing.

k.florin@theday.com