American antivirus software pioneer John McAfee, wanted for questioning over the murder of his neighbour last month in Belize, claimed on Tuesday to have made it out of the country to Guatemala.

"It was not easy to exit Belize and required many supporters in many countries," 67-year-old McAfee, who has been on the run for more than three weeks, since US expat Gregory Faull's 11 November murder, wrote on his blog.

"I am in Guatemala and will be meeting with Guatemalan officials this morning. If all goes well I will do a press conference tomorrow (Wednesday)," wrote the fugitive, believed to be travelling with his girlfriend Sam (20).

McAfee, who maintains his innocence, has been posting regularly on his blog, whoismcafee.com, leaving a confusing trail for the public and the Belizean authorities to follow.

Before apparently fleeing south into Guatemala, he put out a false report saying he had been captured near the northern Mexican border and claimed to have sent a "double" with a North Korean passport to Mexico as another decoy.

Internet users tracked a photo from a magazine on Monday to Guatemala, but McAfee initially claimed to have encrypted it to throw police off the scent.

"I apologise for all of the misdirections over the past few days," McAfee, who says he is also travelling with two reporters from Vice magazine, wrote in Tuesday's post.

"Yesterday was chaotic due to the accidental release of my exact co-ordinates by an unseasoned technician at Vice headquarters," he said.

"We made it to safety in spite of this handicap. I had to cancel numerous interviews with the press yesterday because of this and I apologise to all of those affected."

Police say Faull (52) was discovered by his housekeeper with a 9-mm slug in his head lying in a pool of his own blood.

Prior to his murder, Faull had led neighbours in writing a letter to the mayor complaining that McAfee's "vicious" dogs and aggressive security guards were scaring tourists and residents alike.

McAfee shot dead four of his dogs before fleeing, claiming they had been poisoned, possibly by Faull.

Police said the dogs were exhumed last week and ballistics experts are seeing if the slugs match up with the one found in Faull's head.

A successful Silicon Valley entrepreneur who cashed out to live the life of an adventure seeker, McAfee amassed huge wealth from the antivirus software that bears his name.

He decamped to Belize in 2009 after losing an estimated $96-million of his $100-million fortune due to bad investments and the financial crisis.

According to profiles in The New York Times and tech magazine Wired, his lifestyle became increasingly extreme as he descended into a drug-fuelled existence centred on young prostitutes.