Little League Coach Terrorized by Disgruntled Parent

March 28, 2014— -- A Little League coach and his family said they feared for their safety when their East Meadow, N.Y., neighbor terrorized them for a year with threatening anonymous letters because her son failed to make the summer travel team.

"We spent days, months, years ... looking over our back," John DeMasi told ABC News' "20/20."

It began in the summer of 2010, when DeMasi was coaching his son Dominic DeMasi's baseball team. An angry letter was sent to the league claiming DeMasi was playing favorites as a coach.

"It was just [an] anonymous letter sent [about] how wrong I was coaching the team and how bad we were," DeMasi said.

Soon, more letters arrived, each one containing increasingly more specific and personal information about DeMasi. He and his family became scared for their lives, DeMasi said.

"I know where your wife goes every day. I know where your daughter goes to dance school," John DeMasi's wife, Linda DeMasi, recalled one of the letters saying.

Linda DeMasi said she became so fearful that she stopped working part-time. "I didn't feel safe with, you know, somebody else driving my children," she explained. "I was afraid."

While the letters continued to frighten the DeMasi family, they found comfort in their new friendship with Janet Chiauzzi, a neighbor whose son had played baseball with Dominic DeMasi. Chiauzzi had begun working her way into the DeMasi family's lives.

"Janet was texting me every other day," said Linda DeMasi. "We were with the same circle of friends." The pair attended the same events. Chiauzzi even showed up at Linda DeMasi's 40th birthday party.

Then, in the spring of 2011, two more letters arrived in the DeMasi family's mailbox. One letter was addressed to John DeMasi, and the other was addressed to his then 10-year-old son Dominic.

Read the full letter sent to John DeMasi's son Dominic Demasi here.

One part of the letter addressed to John DeMasi said, "I made it my life's goal now to observe your family on a 24/7 basis. ... Just tell your wife and kids to watch themselves, especially at night."

"I read the letter written to my son, which ... took me down because it just said that, 'If your father doesn't step back, I'm going to kill him,'" John DeMasi said.

Refusing to give into the letter's demand, John DeMasi continued to manage the team, with his terrified son still on the team.

"I definitely got nervous. Every time I went up to bat, I felt someone was always watching me. It definitely made the game more nerve-wrecking and harder to deal with," Dominic DeMasi told "20/20."

Days later, John DeMasi's children were pulled out of school and interviewed by Nassau County Child Protective Services. "Because the school had received a letter saying that I was abusing my children, so my kids were spoken to, interviewed to basically see if their father beat them," John DeMasi said.

While the investigation by state social workers found the abuse allegations baseless, Nassau County Police were deep in their own investigation of who was sending the letters to the DeMasi family.

Police focused on the envelopes that the letters were sent in. The addresses on the envelopes were all written in the same handwriting and used the exact same stamps.

"That made it apparent that were we dealing with the same person on each occasion," Nassau County Police Detective Lieutenant Raymond Cote told "20/20."