The PSNI said they have searched Mr Beattie's house as part of an "ongoing investigation"
Beattie, who spoke to
sundayworld.com last week offering an apology to the family of nationalist politician Denise Mullen for murdering her father, Denis Mullen five decades ago, saying Mr Mullen was “totally innocent”.
He served 16 years in prison for murdering the 36-year-old ambulance controller in the Moy in 1975.
He also murdered Pat McNeice in Loughgall in 1976 and Fredrick McLoughlin in 1976.
He was found guilty in Dungannon Magistrate’s Court two weeks ago for sending Ms Mullen an abusive letter with the aim of getting her to drop legal proceedings against him.
Now it has emerged Beattie’s Annaghmore home was searched last Tuesday by the PSNI.
Nothing was found in the search which was carried out under the Firearms Order of 2004.
The PSNI confirmed the search was carried out as part of “an ongoing investigation” and that “no items were seized and no arrests were made”.
“Enquiries are continuing”, they added.
The search was conducted just days after the conviction of Beattie for penning the letter which he attributed to ‘Mid Ulster UVF’.
Sunday World spoke to Mr Beattie he claimed he is currently being targeted by British secret service agents and is preparing to go to jail when he is sentenced next month.
After the particular shocking murder of Denis Mullen, when authorities arrived on the scene, they found the deceased man’s four-year-old daughter in her nightie, covered in blood, desperately trying to revive her father.
Now an artist, Beattie told us he was given a sinister warning, which he believes the secret service was behind, while out on his bicycle recently.
He said: "Without doubt this was a warning. It's how the spooks operate.
"I was out on my bike for a bit of exercise. I was coming up a long slow hill. Suddenly a van appeared over the brow of the hill. I know every vehicle around here, but I'd never seen this one before.
"I couldn't believe it when I saw it come over the white line in my direction. I braked on the bike because I thought he was going to knock me off the road.
"At the very last minute, the van swerved off and as it did so, the driver waved at me.
"It definitely was a serious warning. I tried to report it to the police, but I couldn't get through."
Speaking of the murder of Mr Mullen, he said: "Denis Mullen was an entirely innocent man.
"It actually broke my heart when I realised I had killed an innocent man. He was a totally harmless being.
"I'm saying that on the record and I want Denise and her mother to know that.
"I can't go into detail, but although I killed Denis Mullen, other people were responsible.
"I took to the drink - I was drunk every night of the week when I found out I'd killed an innocent man - before I went to jail.
"I was used. But I'm really sorry I did it."