Fore! Score a bogey for Big Dig

It has been called a boon doggle, a crime scene, and countless expletives spewed by drivers stuck in traffic.

Now authorities are investigating how the Big Dig -- or, more precisely, a structure built for the project -- became something else: the site of an unauthorized indoor driving range for state troopers who love golf.

A Massachusetts Turnpike Authority spokesman said yesterday that State Police officials had confirmed that troopers in a motor cycle unit had set up a net in a cavernous room in a Big Dig ventilation building in East Boston so they could drive golf balls. The unit has offices in the building for about a dozen troopers.

John Cogliano, chairman of the authority, first heard about the driving range Wednesday night in a WBZ-TV news report and contacted the superintendent of the State Police, Colonel Mark F. Delaney, yesterday morning, accord ing to Jon Carlisle, the authority's spokesman.

State Police officials told Cogliano that they had removed the net a couple of weeks ago and are conducting an internal investigation into the matter, said Carlisle, who added that he had few details.

"Chairman Cogliano feels it's entirely inappropriate to have this kind of recreational facility in a public building," Carlisle said. "He was very surprised by this information."

The building, which is located near Logan Airport, is one of seven built by the authority to suck out dirty air from Big Dig tunnels and pump in fresh air, Carlisle said. Carlisle said he heard that the driving range was on the third floor, where the ceiling is at least 25 feet high.

There is no evidence that authority employees swung golf clubs there, he said, but the agency is checking.

Major Michael C. Mucci -- commander of Troop E, which includes the motorcycle unit -- began investigating the driving range earlier this week after a WBZ reporter contacted Attorney General Martha Coakley, who referred the matter to the State Police, said Lieutenant William Powers, a State Police spokesman.

Powers, who characterized the matter as an allegation, said the internal investigation will be completed within a day or two.

"The investigation has three quick parts, " he said. "Did, in fact, a net exist? If it did exist, did troopers use it? And if they did, were they on duty or off duty at the time?"

If there's one thing the Big Dig does not need any more of, it is controversy.

The project, which was expected to cost $2 billion when it was designed in the mid-1980s, has been plagued by cost overruns and reluctance by officials to acknowledge them. Earlier this month, state officials disclosed that its final price tag could be close to $15 billion, although they hope that cost recovery from contractors and other income keeps it closer to $14.6 billion.

A special state prosecutor appointed by Coakley has been calling witnesses before a grand jury to determine whether anyone should face criminal charges in the design and construction of the Interstate 90 connector tunnel ceiling, a section of which collapsed in July, killing a Jamaica Plain woman.

The collapse led to the resignation of the authority's chairman, Matthew J. Amorello. When Cogliano replaced Amorello, he pledged to make the authority more publicly accountable.

Jonathan Saltzman can be reached at jsaltzman@globe.com.