(Reuters) - The mother of the Florida man accused of mailing 15 pipe bombs to prominent Democrats and other critics of U.S. President Donald Trump said her son had long suffered from mental illness in a letter sent to ABC News, the network reported over the weekend.

Cesar Altieri Sayoc is pictured in Ft. Lauderdale, Florida, U.S. in this August 2015 handout booking photo obtained by Reuters October 26, 2018. Broward County Sheriff's Office/Handout via REUTERS

“My son has been ill for a long time and my family and I have tried, over and over again, without success to urge him to get the help he needs,” Madeline Sayoc wrote.

She wrote that she was shocked to see Cesar Sayoc, her son, arrested and charged last week with mailing the devices to former President Barack Obama, Bill and Hillary Clinton, Joe Biden and other high-profile Democrats.

Cesar Sayoc, a former male stripper, pizza delivery driver and disc jockey who lived in a white van festooned with right-wing political images supporting Trump and lambasting his critics, faces a maximum penalty of 48 years in prison.

None of the devices exploded and no one was injured.

The mailed bombs and the massacre of 11 Jews at a Pittsburgh synagogue in late October took place against the backdrop of highly charged political campaigns ahead of Tuesday’s congressional elections.

In her letter, Madeline Sayoc urged Trump, a Republican, and other leaders to tone down rhetoric that could seen as inciting violence.

“Our political leaders, like our President Donald Trump, need to recognize that there are many sick people in this country who take their rhetoric and words of ‘War with the Media’ and ‘War with the Democrats’ to heart,” she wrote.

Cesar Sayoc agreed last week to be transferred to face charges in New York state. It is not clear how mental illness might figure in a defense should he go to trial.

“While I have not lived with my son for 35 years or even heard from him in over four years, I cannot express how deeply hurt, sad, shocked and confused I am to hear that my son may have caused so many people to be put in fear for their safety,” Madeline Sayoc wrote, according to excerpts ABC published on Sunday. “This is not how I raised him or my children.”

Ronald Lowy, a lawyer for Madeline Sayoc, confirmed the authenticity of the letter.