The prospect of a pardon for the notorious frontier figure drew international attention to New Mexico, centering on whether Billy the Kid had been promised a pardon from New Mexico's territorial governor in return for testimony in killings he had witnessed.
But the facts of the case didn't support a pardon, Richardson said Friday on ABC's "Good Morning America." He had been formally petitioned to grant one.
The proposed pardon covered the 1878 killing of Lincoln County Sheriff William Brady. Billy the Kid was shot to death by Sheriff Pat Garrett in 1881, a few months after escaping from the jail.
Garrett's grandson, J.P. Garrett of Albuquerque, sent an e-mail to The Associated Press: "Yea!!! No pardon! Looks like it will be a great new year!!!!"
According to legend, Billy the Kid killed 21 people, one for each year of his life. But the New Mexico Tourism Department puts the total closer to nine.
Richardson, the former U.N. ambassador and Democratic presidential candidate, waited until the last minute to announce his decision. His term ends at midnight Friday.
The historical record on the pardon is unclear, and Richardson staff members told him in August there are no written documents "pertaining in any way" to a pardon in the papers of the territorial governor, Lew Wallace, who served in office from 1878 to 1881.
Richardson said he decided against a pardon "because of a lack of conclusiveness and the historical ambiguity as to why Gov. Wallace reneged on his promise."
Sheriff Pat Garrett's grandson J.P. Garrett and Wallace's great-grandson William Wallace expressed outrage over a pardon after Richardson set up a website in mid-December to hear from the public.
The website was established after Albuquerque attorney Randi McGinn submitted a formal petition for a pardon. Richardson's successor has criticized him for considering the pardon.
"We should not neglect the historical record and the history of the American West," Richardson said.
His office received 809 e-mails and letters in the survey that ended Sunday, with 430 favoring a pardon and 379 opposed. Comments came from all over the world.
McGinn argued that Lew Wallace promised to pardon the Kid, also known as William Bonney or Henry McCarty.
She said the Kid kept his end of the bargain, but the territorial governor did not.
The Kid was a ranch hand and gunslinger in the bloody Lincoln County War, a feud between factions vying to dominate the dry goods business and cattle trading in southern New Mexico.
Richardson has said the Kid is part of New Mexico history and he's been interested in the case for years. He's also pointed to the "good publicity" the state received over the pardon.
J.P. Garrett said there's no proof Gov. Wallace offered a pardon -- and may have tricked the Kid into testifying.
"The big picture is that Wallace obviously had no intent to pardon Billy -- even telling a reporter that fact in an interview on April 28, 1881," he wrote. "So there was no 'pardon promise' that Wallace broke. But I do think there was a pardon 'trick,' in that Wallace led Billy on to get his testimony."
He also said that when the Kid was awaiting trial in Brady's killing, "he wrote four letters for aid, but never used the word 'pardon."'
William Wallace of Westport, Conn., said his ancestor never promised a pardon and that pardoning the Kid "would declare Lew Wallace to have been a dishonorable liar."
Billy the Kid killed two deputies while escaping jail. McGinn's request did not cover those deaths, but Richardson said he had to consider them in his decision.
The Kid wrote Wallace in 1879, volunteering to testify if Wallace would annul pending charges against him, including a murder indictment in Brady's death.
A tantalizing part of the question is a clandestine meeting Wallace had with the Kid in Lincoln in March 1879. The Kid's letters leave no doubt he wanted Wallace to at least grant him immunity from prosecution.
Wallace, in arranging the meeting, responded: "I have authority to exempt you from prosecution if you will testify to what you say you know."
"It seems to me that when the government makes a deal with you, it should keep its promise," McGinn said after filing the request.
But when the Las Vegas, N.M., Gazette asked Wallace shortly before he left office about prospects he would spare the Kid's life, Wallace replied: "I can't see how a fellow like him should expect any clemency from me."
J.P. Garrett also contended Richardson should have designated an independent, impartial historian, and noted that Richardson appointed McGinn's husband to the state Supreme Court. McGinn has "meager qualifications" and a possible conflict of interest, William Wallace said.
McGinn insisted her only tie to the administration was in volunteering to look into the issue, knowing Richardson's interest.