Story highlights

All five victims had been shot, and two suffered blunt-force trauma

No motive for the killings has been established, police say

Person of interest is suspect in attempted armed robbery of drugstore in May

CNN  — 

A man arrested 4 ½ months after an attempted armed robbery of a pharmacy is now also considered a person of interest in the recent slayings of five people, Indiana authorities said Wednesday.

David E. Ison, 46, of Glenwood, Indiana, is being held in the Ripley County Jail on an attempted armed robbery charge, said Sgt. Jerry Goodin of the Indiana State Police.

While a person of interest in the weekend deaths in rural Franklin County, Ison has not been charged in the killings, state police said in a statement.

A warrant was issued Tuesday in the May 9 attempted armed robbery of the store in Osgood, Indiana. According to police, Ison left unspecified DNA at the pharmacy before he escaped. A positive match was made to Ison, officials said.

Ison was put under surveillance Tuesday and picked up during a traffic stop in Franklin County, Goodin said.

During the arrest, detectives from the Indiana State Police Post at Versailles “developed information” that may link him to the five victims, the state police statement said.

Authorities got a search warrant and went to a residence in Glenwood where Ison had been staying, police said.

“Along with the information gained from their search warrant, along with the information gained from the arrest … we feel fairly confident that we have a very good person of interest in the murders,” Goodin said.

Franklin County Sheriff Ken Murphy said investigators were trying to ascertain whether there may be additional arrests in the case.

The victims were identified as Roy D. Napier, 50; Angela Napier, 47; Melissa Napier, 23; Jacob Napier, 18; and Henry Smith, 43. All five were residents of Laurel, Indiana, authorities said.

The Napiers all had been shot in the head, Coroner Wanda Lee said, and Angela Napier also had suffered blunt-force trauma to the head. Henry Smith had been shot in the chest and also suffered blunt-force trauma to the head, the coroner said.

Authorities first got a call Sunday afternoon from people concerned about a small child wandering near the street near Laurel, in eastern Indiana, about halfway between Indianapolis and Cincinnati. Not seeing any adults around, some adults stayed with the child until police arrived.

After “gaining more information” by talking with the child and neighbors, a Franklin County sheriff’s deputy requested help. That led to the discovery of a dead man at one address and four other fatalities – two males and two females – at an address across the street, Goodin said.

“This is a very heinous crime,” Goodin said. “We want to make sure we get every single person responsible that has any responsibility in this crime, to stand in the front of the courts for what their role or their involvement was.”

Information gathered in the investigation will be forwarded to the Franklin County Prosecutor’s Office, officials said.

CNN’s Maggie Schneider and Jake Carpenter contributed to this report.