Detectives are waiting for the medical examiner to determine the man's cause of death, Everett police officer Aaron Snell said Friday.
That could take some time, he said. The death was reported Thursday.
If the man's death is connected to injuries from the August robbery, police may have a homicide investigation on their hands.
"At that point, depending on what those results are, then we can make some kind of assessment and figure out where we're going to go from there," Snell said.
The man's name wasn't formally released, but he was identified in other media reports as Harold Caywood, of Everett.
The suspect in the robbery, Patrick Hartness, 26, of Everett, is in custody at the Snohomish County Jail. He was charged in September with first-degree robbery.
Earlier this week, the Everett police Major Crimes Unit released a bulletin saying that Hartness allegedly had been involved in a series of burglaries and other crimes targeting older victims.
In the Aug. 24 robbery, the 91-year-old man was walking into the gas station to pay for gas, according to court papers.
He was holding several hundred dollars in his hand at the time.
Hartness allegedly grabbed the man's wrist and punched him in the face. The older man was knocked to the ground. Hartness then reportedly snatched the money out of the man's hand.
Hartness was caught in a nearby fast-food restaurant bathroom. Police alleged that they found a pair of brass knuckles, drug paraphernalia and a wad of cash in his pocket.
A money clip belonging to the victim was found in the bathroom stall.
At the time of his arrest, Hartness was wanted on warrants for a domestic violence assault and driving with a suspended license. He has previous convictions for auto theft and drug possession.
Detectives also have concluded that Hartness identified victims in their 90s to steal their checks and credit cards, Snell said. He and others then allegedly would cash the stolen checks and withdraw money using the cards.
"It is believed there are additional elderly victims who have not reported burglaries or may not realize they were victimized," Snell said earlier this week.
Potential victims were encouraged to call the police department's tip line at 425-257-8450.
Thursday's death is in no way related to another robbery in Everett this week involving a young man who targeted an older couple. In that case, a 69-year-old man collapsed and was hospitalized after trying to catch the person who snatched a wallet from his wife outside a south Everett business. That man was treated at the hospital and later released.
Rikki King: 425-339-3449; firstname.lastname@example.org
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