KANSAS CITY, Mo. -- An alleged murder-for-hire plot unraveled Tuesday night in Independence, according to prosecutors who filed charges against a suspect.

They charged Robert S. Macklin, 35, of Independence, with first-degree assault or, in the alternative, first-degree conspiracy to commit murder in connection with the alleged plot, prosecutors said in a news release.

According to court documents, Macklin had approached his female roommate several times asking her to kill a woman identified as the girlfriend of a man with whom Macklin had had a relationship.

The roommate contacted police, who arranged for a meeting between Macklin and an undercover officer, prosecutors said.

During the conversation between Macklin and the officer, Macklin offered the officer $5 in cash and 90 OxyContin pills in exchange for the intended victim's death, authorities said.

Once the offer was made and Macklin gave the officer $5 as a down payment, officers took Macklin into custody, according to the prosecutors' news release.

Prosecutors requested he be held on a $500,000 bond.