A LEADING psychologist has said the people behind a recent spate of dog poisonings could be "psychopaths".

Criminologist David Wilson said those who target pets may have a disorder called Zoosadism - meaning they take pleasure in making animals suffer.

His words come after a spate of malicious incidents including dog biscuits being laced with nails, staples and poisonous anti-freeze at locations throughout Glasgow and Lanarkshire.

Cops find it “almost impossible” to nail cruel criminals who deliberately try to poison dogs in public parks.

And animal welfare charity the Scottish SPCA received reports of more than 54 dog poisoning cases in the last year – but none of the perpetrators have been convicted.

Professor Wilson suggested the “generic” poisoning incidents in public parks could be a result of something a lot more sinister.

READ MORE: Glasgow owner of 'devil dog' boasted pet would rip animals apart

He said it’s likely perpetrators of premeditated dog poisoning are either psychopaths or suffering from an undiagnosed form of psychosis.

Professor Wilson, the founding director of the Centre for Applied Criminology at Birmingham City University, believes perpetrators could even have Zoosadism, which means they gain pleasure from cruelty to animals.

He explained: “In research literature it’s called IATC which means intentional animal torture and cruelty.

“These aren’t targeted attacks and they’re much more generic.

“When you’re dealing with much more generic attacks, then it would be either a form of paraphilia or zoosadism.

“Some people who gain sexual pleasure out of torturing or being cruel to animals.

READ MORE: Glasgow woman’s warning as dog dies after swallowing poison in park

“But because this particular perpetrator wouldn’t necessarily see these animals being harmed or in distress, again you’re probably dealing with another form of intentional animal torture and cruelty, which reveals something about the underlying mental health of the person who is engaging in these behaviours.

“They will often have a personality disorder such as psychopathy or they may be experiencing some form of psychosis, which are two very different things.

“If you’re dealing with psychopathy, cruelty to animals has sometimes been seen as one of three factors that can predict violent behaviours, as well as bed-wetting and fire starting.

“If this is one particular perpetrator as opposed to several, then you can also think about IATC as being about spite and revenge.

“You can sometimes see people who are cruel to animals in this way but have not targeted a specific animal, just as a way of exerting some form of revenge on people who might be dog owners.

“Therefore he gains revenge on a specific dog owner by being cruel to dog owners more generally.

“It’s a very diverse phenomenon and these people seem to be targeting dogs as a specie in general.”

Scottish SPCA Chief Superintendent Mike Flynn found it difficult to explain the motives behind the twisted individuals targeting the animals.

READ MORE: Glasgow dog owner’s heartbreak as dog dies after swallowing poison

He said: “We’ve had 54 dog poisonings since January 2018 but the problem you’ve got is that it’s so hard to detect.

“The nails being left in dog biscuits is new to me but that is obviously a deliberate act – there’s no way that could be accidental.

“If you go into one of these public parks, there’s around 100 people walking about and somebody just deliberately drops this, the chances of finding that person are slim.

“We’ve maybe caught four or five people, but we’ve caught them because they’re out boasting ‘right that’s me got rid of the cats from next door’ and all that kind of stuff.

“Then you find the poison in their premises and that’s how it gets brought to court.

“When you’re talking about in a park that’s probably not somebody targeting an individual animal.

“It’s just some random, very strange person and it’s just sickening.

“They probably don’t realise the damage that they’re doing and if they’d ever seen an animal that’s ingested this kind of stuff and the suffering it can do to them, then they’d really struggle to sleep at night.”

The animal welfare boss spoke out after three dogs apparently ingested poison in Alexandra Park, in Glasgow.

It happened just days after the SSPCA appealed for information after dog biscuits were found laced with nails in Anderston.

One dog walker had to seek urgent treatment for the animals in his care after finding food smelling strongly of household cleaner.

READ MORE: Dog walker warning as poisoned food found in Glasgow's Alexandra Park

Mr Flynn admitted it was almost impossible to catch the perpetrators unless people witness anyone acting suspicious while dropping snacks.

And he warned the poisons could also pose a risk to children as well as cats and dogs.

He said: “We’ve had other reports of neighbours throwing baited stuff over people’s fence as revenge against the owners.

“If you target somebody’s pet then you’re basically targeting the person as well.

“We’ve had everything from anti-freeze poisoning up to strychnine.

“We had somebody over on a sporting shoot with this very expensive retriever dog, it ate a chicken’s head that was laced with strychnine and it died in about 30 seconds. It is lethal.

“If it can kill a dog in 30 seconds, what would have happened if a child had picked it up?

“Some of these poisons could be picked up by kids and some of them can actually be absorbed through the skin.

“So again when you’re talking about dumping dangerous materials in a public place, it could be a child that picks that up.

“That’s why it’s important that if you do see anybody acting suspicious then it’s important to contact the police.

“People will instantly blame the prized gardener round the corner because he hates cats, or pigeon fanciers, but proving that is a totally different thing.”

Read more of today's top Glasgow stories.