INDIANAPOLIS -- The arrest of an Indianapolis man on suspicion of asking an undercover police officer to kill his wife has prompted investigators to re-examine the May death of his daughter, authorities said.

Tow truck driver Robert L. Quarles (pictured), 56, was arrested Saturday and charged with conspiracy to commit murder in connection with an alleged plot to kill his wife, police said.

In light of those allegations, Quarles has become a person of interest in a re-investigation of the May 10 death of his daughter, Jessica Quarles, 22, of Indianapolis, authorities said. The woman, described as mentally disabled, drowned in a bathtub after being placed there by a caregiver, according to police.

Police said they believe Robert Quarles had an affair with the caregiver, and that he and his wife stand to get a $1 million settlement from a health care provider because of his daughter's death.

Police began investigating Quarles this month after one of his Indy Towing Service co-workers told authorities that Quarles had talked about having unsuccessfully tried to poison the wife with an eyewash product, authorities said.

At the direction of police, the co-worker introduced the undercover officer to Quarles as one of the co-worker's cousins, authorities said. Quarles, thinking the undercover man was a professional killer, tried to hire him to kill his wife, according to police.

Police said Quarles offered the undercover officer $1,500 to kill his wife. Authorities said they believe Quarles hoped to collect $20,000 in life insurance had his spouse died, and that he didn't want to share the potential $1 million settlement in connection with his daughter's death.

"Almost all of our murders for hire are exactly like this as far as how cold and calculating the suspect is," said Indianapolis police Lt. Dave Young, the case's lead investigator.

Police said Quarles gave the "hit man" the schedule of his wife, who works at an Indianapolis pharmacy.

Quarles later told his co-worker that he was becoming frustrated with the plan and that he was thinking about saving money by taking things into his own hands, police said.

Quarles was being held Thursday without opportunity for bail at the Marion County Jail.

A jury trial in the case is scheduled to start Feb. 4.