A Mount Pleasant police supervisor’s squabble with a resident over the department’s handling of a sewage spill last summer culminated with his resignation, according to documents released this week.

Lt. Ben Marlow turned in his badge in mid-September after an internal investigation started reviewing possible unbecoming conduct and unauthorized release of department records.

At its heart was a resident’s gripe that Marlow was sarcastic and rude during a telephone call in which the woman asked him why some — but not all — motorists were being detoured around the sewage breach. To her, the traffic-control measure didn’t make sense, and Marlow refused to explain it, she wrote in an email to the town’s police chief.

But Marlow, who had spent much of his 18 years in the agency as a traffic officer, was equally perturbed by what he called the resident’s insulting and dismissive attitude — so he filed his own grievance with the vice president of the bank where the woman works.

In his email to the official, Marlow expressed department-wide outrage that the employee lodged the complaint from a bank telephone “on your dime.” Marlow attached a recording of what he dubbed a “completely unacceptable” phone call.

Two weeks after the quarrel, Marlow was placed on paid leave. He resigned two days later.

The Post and Courier looked into the ordeal after readers expressed concern about the lieutenant’s departure. The newspaper obtained 16 pages of documents pertaining to the case through a S.C. Freedom of Information Act request.

Town police officials said they could not further discuss the personnel matter. Attempts to contact Marlow were not successful.

He is the second Police Department supervisor to resign this year amid an internal investigation. Maj. Frank Riccio, the agency’s second in command at the time, quit in March after he was arrested on a drunken-driving charge.

Marlow does not face criminal charges.

Before joining the department in July 1994, he served two years on the University of South Carolina’s police force.

He is certified to teach firearms courses and to operate radar and breath tests, according to police academy records.

Marlow commanded a 10-officer, six-firefighter team that the town sent in 2005 to Biloxi, Miss., where the squad patrolled for looters after Hurricane Katrina.

On Aug. 29, Marlow was one of the police officers involved with altering traffic flow on Rifle Range Road after 500,000 gallons of sewage spilled south of the Isle of Palms Connector the day before.

Leigh Stewart, a resident of the Sweetgrass subdivision on Rifle Range Road, later reported that a police officer directed her to turn right and travel in a roundabout way toward her job as manager of the Park West branch of Tidelands Bank.

Stewart, in later complaints, said she didn’t understand why she couldn’t turn left when traffic was moving in both directions on Rifle Range Road.

An officer on the scene wouldn’t explain it to her, so she contacted the Police Department and asked for someone to return her call. That someone was Marlow.

At Stewart’s request, the lieutenant called her at work. He told her that engineers had designed the traffic pattern in response to the sewage spill, according to a transcript of the call.

But Stewart pressed Marlow for a more precise reason for the detour that she said had inconvenienced her.

In the complaint she later emailed to Police Chief Harry Sewell, Stewart said that the lieutenant grew increasingly facetious and interrupted her during their chat.

“I am so sorry you were inconvenienced by the thousands of gallons of sewer in front of your neighborhood,” he said during the call.

Marlow suggested that Stewart’s banking career provided her little insight into traffic control, according to her complaint.

Stewart, who could not be reached for direct comment, later told the chief that she wanted officers to treat residents with “common courtesy” and said that people like her deserve a “reasonable explanation” for police actions.

But Marlow took equal offense to Stewart and spoke out.

In his email to Scott Garcia — senior vice president with Stewart’s employer, Tidelands Bank — Marlow compared their conversation with the times he had been cursed at, spit on and threatened by criminals and people with mental-health issues.

Stewart accused him of not treating her in a Christian way and called him a “smartass,” he pointed out. Such accusations revealed the bank’s “clear religious preference,” he wrote.

When police officials later questioned Marlow about his exchange with Stewart and his email to her boss, he said his own church involvement had played a vital role in achieving personal happiness recently.

“We are outraged that an employee in your service, while on your dime,” Marlow wrote in his email to the bank official, “has the authority and latitude to curse me and then criticize me based on her measurement of Christian inadequacies.”

Marlow told his own bosses that he sent the email from a personal account, but he couldn’t remember whether he used a town computer to do so.

Reach Andrew Knapp at 937-5414 or twitter.com/offlede.