East Hampton Town police have charged Scott A. McKallip, 56, with third-degree arson, a felony, for a December fire at East Hampton Indoor Tennis. Mr. McKallip, an ex-Marine from East Hampton Village, was arrested on Saturday following a four-month investigation that included Suffolk County arson detectives. Arson investigations take time, East Hampton Town Detective Sgt. Dan Toia said Tuesday, adding that once police had the probable cause they needed, they made the arrest. Police believe he acted alone. Suffolk County Arson detectives were called in soon after the East Hampton Fire Department extinguished the Dec. 22 blaze at East Hampton Indoor Tennis on Daniel’s Hole Road in Wainscott. The property is also home to the Clubhouse, which has a restaurant, bar, bowling lanes, and an arcade. At around 5 a.m., an automatic fire alarm summoned a fire chief to the property, where he found heavy smoke coming from a building used as a reception area for the tennis club. A sprinkler system helped to squelch the fire before too much damage was done to the building.Town police said at the time that it appeared “some sort of accelerant” had been used, but they stopped short of calling it arson in the days after the fire, instead choosing to wait on results of the investigation. On Dec. 23, the morning after the blaze, an employee at the complex alerted police that Mr. McKallip was on the property. Mr. McKallip had caused trouble for Scott Rubenstein, the facility’s managing partner, before. He had previously sent Mr. Rubenstein’s adult daughter, who works at the businesses, threatening messages on Facebook. He was charged first in Dec. 7 with aggravated harassment, a misdemeanor, and an order of protection was put in place by East Hampton Town Justice Lisa R. Rana prohibiting him from going to the Rubensteins’ home or businesses. He had been freed on $300 bail. When police found him in the parking lot at the Clubhouse on Dec. 23, he was arrested for trespassing and violating the court order. As police questioned him, it came to light that he had also been on the property on Dec. 21 at about 6 p.m., less than 12 hours before the fire, police said at the time. He was charged with violating the court order on that date as well. He posted $500 bail on Dec. 24 on the new charges.After The East Hampton Star published a story about Mr. McKallip’s trouble at the tennis complex during the weekend of the fire, Mr. McKallip visited the Star office, distraught about the article. He stated that he had set the fire. East Hampton Village police escorted Mr. McKallip from the building. No charges were filed.Soon after, on New Year’s Eve, he was back in police custody after making threats about Mr. Rubenstein at Fierro’s Pizza in the village. (Mr. Rubenstein was not in the pizza place, The Independent reported.) He was charged with felony criminal contempt for violating the terms of the order of protection, which included not making threats. He was held on $5,000 for five days in the Suffolk County jail, until he had to be released because the Suffolk County District Attorney’s office had not indicted him. Detectives had planned to take Mr. McKallip into custody on the arson charge on Monday, but an incident at the East Hampton I.G.A. moved up their timeline. Mr. McKallip allegedly stole $15.84 in groceries from the North Main Street store on Saturday morning and fled on foot when confronted, police said. Officers caught up with him and charged him with misdemeanor petty larceny.Justice Rana arraigned Mr. McKallip on the arson and petty larceny charges in East Hampton Town Justice Court on Sunday morning. She ordered him held on $50,000 cash or $150,000 bond. He is due back in court today. The investigation is ongoing. Police have asked anyone with information to call detectives at 631-537-7575. All calls will be kept confidential.