Security personnel for the controversial Mariner East pipeline engaged in an illegal “buy-a-badge scheme,” recruiting state constables to act as private guards at local construction sites and taking steps to obscure payments to them from public scrutiny, Chester County District Attorney Thomas P. Hogan said Tuesday.

Hogan’s office brought criminal charges against Frank Recknagel, 59, the head of security for pipeline operator Energy Transfer Partners, and four security contractors hired by the firm: Nikolas McKinnon, 39; Michael Boffo, 59; James Murphy, 61; and Richard Lester, 71.

All were charged with bribery, conspiracy, and related offenses. They are accused of paying 19 constables more than $230,000 over two years to improperly patrol the pipeline route while wearing their uniforms and badges and carrying their firearms to act “as a deterrent,” according to court documents.

“This is a pretty simple case,” Hogan said in a statement. “State constables sold their badges and official authority. Energy Transfer bought those badges and authority, then used them as a weapon to intimidate citizens.”

Constables are elected or appointed to maintain order at election polls, but may also use their authority to serve warrants, complaints, or subpoenas, and transport prisoners.

Vicki A. Granado, a spokesperson for Energy Transfer Partners, said the company found the charges against Recknagel “troubling" and without merit.

"The district attorney’s complaint only constitutes allegations — it is not proof of wrongdoing,” she said. “Energy Transfer will fully support [Recknagel] as he seeks the dismissal of the allegation, which, again, we believe has no merit, now that he is entitled to due process and a fair hearing.”

Granado said local law enforcement officials did not object to the company’s plan to hire constables when it was discussed with them. Later Tuesday, West Whiteland Township police said they were unaware that the company had hired constables for security. Energy Transfer, they said, told them the company had hired a private security firm.

Sunoco Pipeline, a subsidiary of Energy Transfer Partners, is building three adjacent pipelines to transport natural gas liquids such as propane across the state from the Marcellus Shale region through Chester County to a terminal in Marcus Hook.

Earlier this year, Hogan launched a criminal investigation into the pipeline, which has garnered near-constant protest from residents living along its intended route. A similar investigation is underway by state Attorney General Josh Shapiro.

More recently, federal investigators launched a probe into how Gov. Tom Wolf’s administration issued construction permits for the $5.1 billion project.

The charges filed Tuesday were built on an investigation Hogan’s office conducted this summer. In August, two constables, Kareem Johnson, 47, and Michael Robel, 58, were charged with official oppression and Pennsylvania Ethics Act violations for improperly working for Raven Knights, a security firm owned by Lester and operated by Murphy.

» READ MORE: 2 state constables broke law while working for Mariner East pipeline, Chester DA says

Chester County detectives said Johnson and Robel, in uniform and carrying weapons, were paid to patrol pipeline construction sites. Robel once approached a county detective, identified himself as working for “Sunoco," and ordered the detective to move his legally parked vehicle. Their criminal cases are pending in Chester County Court.

McKinnon and Boffo are affiliated with TigerSwan LLC, which is in litigation over accusations it operated without a license while working as a contractor for Energy Transfer to help secure the Dakota Access Pipeline in North Dakota, a site roiled by protests in 2016.

In the affidavits of probable cause for Tuesday’s arrests, detectives said Recknagel, the head of security for Energy Transfer, arranged to “offshore” the hiring of the constables through TigerSwan and Raven Knights.

Recknagel hid the payments to the constables through a “shell game," investigators said: He sent their payments to JAB Inspections, another Energy Transfer subcontractor, which had “no operational control over the security team." JAB then forwarded the payment to Raven Knights.

Murphy and Lester, both former Pennsylvania state troopers, then cut checks for the constables without official tax documentation, “in a manner that evaded reporting requirements,” according to the affidavits.

The constables made the transactions harder to track by failing to report the money on their annual state ethics statements, as required by law. “Every step of the payments was hidden and cloaked,” according to the affidavit.