Most times, talks at Chadds Ford Business Association lunches revolve around business. Not so during the May 7 lunch at the Pennsbury Township Building.

Author, historian and former newspaper editor Bruce Mowday gave members of the Chadds Ford Business Association a brief glimpse into the activities, the investigation into and the downfall of the notorious Johnston gang in Chester County.

Mowday recently wrote a book on the Johnston’s “Jailing the Johnston Gang: Bringing serial murderers to justice.” The book is published by Barricade Books.

Johnston family members and associates terrorized southern Chester County for years in the 1970s and they murdered at least 10 people from 1977 to 1978.

“They killed six people, at least. Bruce Johnston Sr. was convicted of six murders. I think he did 10,” Mowday said. “And some people think he did more.”

As a reporter, Mowday covered the trials of gang members and was in the field while investigators were digging up bodies of the gang’s victims. Some of those victims were family members themselves.

“I was also locked up with Bruce Johnston Sr. for two hours one night,” Mowday said.

He explained that he was locked up while interviewing the elder Johnston, not for any other reason.

While the book goes into the gang’s background and activities, Mowday said the focus is really about the investigators and how they brought gang members to justice.

He said it was a rare investigation in that all levels of government came together without squabbling over jurisdiction. Local and county police agencies, state police agencies from three different states and the FBI all cooperated.

“They were the right people [for this investigation,]” according to Mowday.

Johnston Sr. began his criminal life in the 1950s and wasn’t necessarily cautious about what he said or to whom.

Mowday told one story of how the patriarch, while in jail, told a prison guard what a great criminal he was.

According to Mowday, Johnston was bragging about all the crimes he had gotten away with and that he and his gang had an almost foolproof method. At the time, the state police in Avondale had only two cars and if the gang saw both cars in the parking lot at the barracks, they knew that southern county was wide open for whatever the Johnston’s wanted to do.

“Why you would tell a prison guard that, I’m not sure because [the guard] told the state police and from that day forward you never saw both cars on station,” Mowday said.

The gang went from being petty thieves to becoming more violent. They robbed and beat a couple in Delaware County just after the couple returned home, according to Mowday. The victims were so traumatized they never returned to their home.

The movie “At Close Range” with Sean Penn and Christopher Walken is based on the Johnston gang.

Mowday said when the producers came to Chester County with the script, county officials wanted nothing to do with the production since the script called for making some of the family members sympathetic characters.

Mowday will be at the Chris Sanderson Museum Saturday, May 23 at noon.