The wife of Opposition Leader Kim Swan pleaded for her son's life to be spared in an emotional letter to the family of murdered State Trooper Shawn Blanton.

In the letter, sent to the Blanton family and released by reporter Adrian Acosta at FOX Caroline, Cindy Swan said she wished she could have given her estranged son Edwardo Wong Jr. the psychological help he needed.

Wong Jr., Mrs. Swan's oldest son from a previous marriage, was found guilty of the first degree murder of Trooper Blanton following a routine traffic stop in North Carolina.

His trial is now in the sentencing phase at the Catawba County Supreme Court, with Wong Jr. possibly facing the death penalty.

In the letter, Mrs. Swan wrote: "Words cannot express my deepest sympathy on what my son Eddie Jr. did to your family. From the moment I heard what Eddie Jr. did, I have done what little I can do from afar to send my condolences.

"I have mourned for you as a mother, Mrs. Blanton Sr., and apologise to you personally mother to mother."

While she said she could not defend her son's actions, she asked for compassion, and for her son to have the opportunity to get the treatment he needs.

"Eddie Jr. needs to be removed from society and get proper, long-term psychological counselling and reprograming.

"With proper therapy, I am sure the part of him that's my child can show itself and he can help other inmates face their demons and turn their lives around."

Wong Jr., 40, from Florida, is the one of three children Mrs. Swan had with her first husband, Edwardo Wong Sr., who she met as a teenager in Belize.

When the couple divorced, Mrs. Swan took custody of their two youngest children, while Mr. Wong took custody of his oldest son.

Unknown to Mrs. Swan, Wong Sr. was a head man in the Chinese Mafia, commonly known as the Triad. In 1994, he was killed in federal prison in Atlanta in what was described as a 'five swords' execution.

Mrs. Swan wrote: "I made a decision to remove myself from the family over 30 years ago and had limited relationship/contact with the family due to the fact that we have a totally different ideology of how life works. I believe honest work equals an honest life.

"Eddie Jr. was not a part of our life, chiefly because of his illicit conduct. He would have been welcomed, but that welcome came with rules, regulations and community commitment."

Wong Jr. never denied murdering the State Trooper, but his defence attorney Mark Melrose argued that head trauma suffered as a child caused Wong Jr. to act irrationally.

In a recorded deposition, Mrs. Swan described an incident in which Wong Jr. fell from the fifth floor of an apartment building.

Mrs. Swan wrote: "Hindsight is always 20/20, and there are not many things in life that I would need a do over for, but if I had to do it again, I would have made sure Eddie Jr. received proper psychological help he needed as a child.

"He did fall, and if the policewoman can be found, she can verify what happened.

"Due to his incapacity of making and weighing the consequences of his immediate actions, I beg the court to spare his life."

According to North Carolina Law, all 12 jurors must find in favour of execution in order to have the death penalty carried out.

Mrs. Swan wrote that she did not attend the trial, saying: "I felt I did not have the right to sit behind Eddie Jr., to support his actions of killing Trooper Blanton.

"My conscience, scruples and principles as a mother would not allow me to sit across from Trooper Blanton's grieving family."

Closing the letter, Mrs. Swan left a comment for her son.

"Eddie Jr., you are my son and you know I don't approve of the path you have chosen as an adult, and as Granny would say, 'You can pick your friends but you can't pick your family.'

"I pray for you to seek redemption and forgiveness. I have not had a full night sleep since this horrid tragedy and may never again, but continue to pray to God for strength for the Blanton family and all concerned."

Wong Jr.'s sentencing continues this week.