"This isn't about money. This is about the murder of Emma Schuller."
Little is revealed about Tony's past, other than he worked as a hitman for the local mob since at least 1989 and was an avid golfer. At some point in his career, one of his murders had resulted in his arrest, but his case ended in a mistrial. After that (possibly in response to his near-sentencing), he started living a more seclusive lifestyle and adopted the alias of "Bosola", named after a character in the 17th-century play The Duchess of Malfi. Shortly before "Reckoner", he was hired by Judge Boyd Schuller, the judge presiding his case, who was diagnosed with terminal cancer, to murder several people whose cases he had presided over, most of which were involved in crimes against children.
Tony is first seen attacking Heather Vanderwaal when she discovers the corpse of her husband Ben, whom he murdered just moments ago. Heather then watches as Tony cuts off Ben's hands (as a reference to his molestation of his stepdaughter) before he abducts her. He later releases her, as she isn't in his hit-list, and she is eventually found and taken to a hospital. Sometime later, he is called to a meeting by Ray Finnegan, a local mobster. As Ray waits for him, Tony suddenly sneaks up behind him, having overheard a phone conversation between him and Garcia, and murders him, having realized the meeting is a setup staged by the FBI. After Schuller is arrested by the BAU, Tony kills Dan Patton, a man who was acquitted for killing Schuller's wife while driving drunk. Meanwhile, the BAU learn Schuller paid for two kills when Patton was allegedly supposed to be the last victim. They then realize Tony was paid to kill Schuller himself, apparently to spare him the pain of slowly dying from cancer. However, they are unable to save Schuller, and he is shot, apparently from a distance. The BAU then departs from Commack while Tony escapes to Florida. At the end of the episode, Tony prepares to leave a golf course after finishing a game of golf, but he is confronted by an armed Sean, one of Ray's enforcers. Tony calmly tries to tell him a joke, but he is shot twice by Sean, who then kills him with a shot to the head.
Tony would only meet his clients in person once, usually just long enough for them to tell him who his target(s) is/are would and later communicate with them on the phone. He usually used a .22 zip gun to kill his victims, firing one shot into the heart and one into the brain, always at close range since the homemade guns didn't have a lot of stopping power.
There were some variations with each murder when he was hired by Schuller. As these victims were all in some way involved in child abuse, Tony would mutilate or torture them in some way appropriate to their crimes. While Rita Haslat was abducted from her home and taken to an unspecified (presumably secluded) location, the male victims on Schuller's hit list (besides himself) were killed in their homes. In the case of Dan Patton (the primary source of Schuller's rage), who wasn't involved in a child abuse case, he was repeatedly bludgeoned with a baseball bat before being killed to make his injuries appear similar to the ones Schuller's wife got from being hit by Patton's car. After killing Ray Finnegan, he mutilated him by cutting his tongue out; Finnegan was not on Schuller's hit list, but he was killed out of necessity as he was helping Rossi and the BAU close in on him. After killing the victims, he would take pictures of the victims with a camera on a tripod as proof of their deaths, uploading and sending the photos to his clients via computer (although he didn't do this after killing Finnegan, since his death was incidental, and Patton). He occasionally took precautions, like cutting the power and covering himself in plastic before killing Ben Vanderwaal. When he killed Boyd Schuller, he did it at Schuller's own request, shooting him from a distance, presumably using some sort of rifle (as homemade firearms like the ones Tony usually used would most likely not reach targets at long distances).
Each of his hits would cost $50,000, which clients would send to a Cayman Islands bank account in five installments of $9,999 (a practice known as "structuring"). This was done to avoid suspicion from the IRS, which kept track of transfers of $10,000 or higher.
Mecacci was profiled by the BAU as one member of a two-person killing team, both members of which are white males. The M.O. of the unsub depicts an efficient, no-nonsense killer who is sophisticated, careful, methodical, and very practical in his crimes. Each mutilation represents the crimes the unsubs believe the victims had committed. The BAU calls this unsub as "The Enforcer". He likely met the first unsub, named by the team as "The Planner", within the court system. The Enforcer has been hired to carry out justice where the courts did not. This justice does not come cheap, so his employer must have access to substantial money. The Enforcer has no intention to let the authorities find the mutilations as the Planner does. He is also armed and extremely dangerous. The Planner would have also committed a mob-related murder and went to trial for it on Long Island in the last decade, which ended in a mistrial and the accused was suspected of being a hitman or enforcer.
- Numerous unnamed victims killed prior to Reckoner, going as far back as 1989
- Pre-October 2008: Unnamed man
- February 4: Rita Haslat (had neglected a number of legal cases, including one of a fatally starved child; was abducted and starved herself for four weeks before being killed)
- July 22: Bill Levington (had been accused of raping a number of minors; his genitals were cut off post-mortem)
- October 7: The attack at the Vanderwall home:
- Ben Vanderwaal (had molested his stepdaughter; was tied to a chair and his hands were cut off post-mortem)
- Heather Vanderwaal (Ben's wife; incidental; knocked out and abducted; was released the next day)
- October 8: Ray Finnegan (incidental; killed for aiding Rossi; his tongue was cut out post-mortem)
- October 9:
- Dan Patton (the drunk driver who killed Schuller's wife; bludgeoned repeatedly with a baseball bat before being killed)
- Judge Boyd Schuller (killed at his own request; was shot in the chest, apparently from a distance)
- Tom Ohmer, the actor who portrays Tony, previously appeared on Criminal Minds, playing a different role in the Season Three episode True Night. In this episode, he had a minor role as a desk sergeant.
- Despite his death, he is the first of five criminals to successfully evade the BAU. The next four are Shane Wyland, Darlene Beckett, The Killer Woodsman, and Taras Yudin.
- Tony's methods of torture and mutilation seemed to have inspired those of many other criminals who would appear in the show's future:
- Thomas Yates restrained and starved his victims before killing them.
- Michael Janeczco removed his victims' genitals post-mortem.
- Hollis Walker cut his third victim's hands off post-mortem.
- Mark Jackson cut his last victim's tongue off post-mortem.
- Peter Folkmore tortured his second and third victims by bludgeoning them with a baseball bat.