PIKETON, Ohio — From her house on Union Hill Road, Brittany Barker heard the first sirens first thing in the morning. She looked out and saw four police vehicles rush past. That was only the beginning.

“They just kept coming, kept coming, and kept coming,” she recalled.

Authorities in this struggling corner of Appalachia were dealing with what turned out to be one of the worst mass killings in Ohio history: Eight family members were shot to death at four homes scattered across a few miles of countryside in what investigators have portrayed as a meticulously planned “execution.” Nearly all were shot repeatedly — one, nine times — and some were also beaten.

What looked to some people like a feud within a family, possibly a murder-suicide, soon took on a more sinister cast when authorities disclosed a large-scale illegal marijuana growing operation at one of the crime scenes and said pot was being cultivated at some of the other homes, too. Ohio’s attorney general also said there were signs of cockfighting at one of the properties.

Nearly a week after the killings, though, authorities have announced no arrests and no motive, an unsettling silence considering the huge investigative force brought to bear in this thinly populated county where many people either knew the victims or knew of them.

Since the discovery of the bodies April 22, over 215 law enforcement officers have been involved in the investigation, with several hundred tips received and more than 50 people interviewed.

Attorney General Mike DeWine has said he doesn’t want to telegraph the killer or killers what investigators know.

Relatives of the victims said they were surprised by the marijuana. Some neighbors said they had heard rumors. And some said the marijuana-growing was a case of courting trouble.

“If you don’t go around bad places, the odds of something bad happening to you are pretty slim,” said Ron Lucas, a paper-mill worker who lives a few miles from where the killings took place.

But Angie Tolliver, a home health aide, said that whatever connection drugs may have had to the slayings, “Nobody deserves that. That’s just evil.”

Large marijuana operations are common in Pike County, scene of the killings. Authorities in 2012 said the seizure of about 1,200 plants in Pike County could be related to a Mexican drug cartel, while in 2010 more than 22,000 plants were confiscated.