FORENSIC analysis of a homemade bomb left in a post box revealed the DNA of a man with a vendetta against the Royal Mail, a court heard.

Iain Merrick, aged 38, is alleged to have planted the device in Winter Hey Lane, Horwich, as part of a campaign against Royal Mail workers for delivering his post to a neighbour.

Susan Cherry, a forensic scientist at LCG Forensics in Warrington, examined the suspicious package and found 13 results matching Merrick’s DNA.

Mrs Cherry said: “The laboratory findings aren’t what you’d normally expect if Merrick hadn’t contributed, but we can’t rule it out. My findings are that it’s more likely he had contributed than had not.”

Not enough DNA was available to make a full profile match and some of the results are thought to have contained more than one person's DNA, the court heard.

The discovery of the device led to a 100 metre cordon being place around the scene and army logistics staff being called to help.

The jury of seven women and five men at Manchester Crown Court yesterday heard how the suspicious package found by postman Ian Platt on April 15, 2011, contained matchstick heads, 26 metal fragments and 35 metal hooks.

The device could have caused injury to the person holding it if the circuit made was connected.

Weeks after the incident a number of typed stickers were found around the Horwich area with the name of a Royal Mail worker, claiming he was a convicted paedophile.

Vanessa Thomson, prosecuting, said months later, in October and November, 2011, six schools raised the alarm, when they received letters containing indecent images of children.

On the back of the images were the names of two Royal Mail staff and their occupations.

DC Michael Mather, formerly of Bolton’s child protection unit, said he and a colleague went to the homes of the named employees fearing the children pictured were theirs.

After speaking with both of them at their homes and looking at photographs of their children they realised they were not responsible for sending the images.

When asked if anyone had a grudge against them they both named Merrick, of Cheriton Gardens, Horwich.

DC Mather said: “Both people were shocked and upset when they found out what had happened and to have a police officer at their door.”

The jury heard Merrick had made numerous complaints to Royal Mail about his post being given to his neighbour and requesting it be delivered only to him.

The defendant was also alleged to have taken photographs of his neighbour, Sylvia Taylor — without her knowledge — and created a video on YouTube containing a montage of images.

Merrick was arrested on suspicion of sending the indecent images of children in October, 2011. He was arrested again in 2012.

Merrick denies sending an explosive substance, 16 counts of making indecent images of children, one count of possessing indecent images of children and four counts of distributing indecent images of children.

The trial continues.