TWISTED yobs have been blasted after shocking pictures of dog biscuits laced with NAILS emerged - in the sixth incident of its kind in a year.

Luckily no animals have been harmed by the evil scheme but an animal welfare charity branded the disturbing finds “calculated” and “abominable”.

The Scottish SPCA slammed those responsible and issued a desperate appeal to track down the culprits.

READ MORE: Glasgow dog poisonings could be work of 'psychopaths'

The first report of the contaminated biscuits in Glasgow was made last year when they were discovered in the Anderston area of the city.

It was followed by two further reports from members of the public were made in March this year.

On three separate occasions since July 8 members of the public have reported seeing them in Dorset Square beside Dorset Street, Glasgow.

Scottish SPCA Inspector Vickery said: “We are grateful that no animal was harmed by the biscuits and we are thankful to the vigilant members of the community who alerted us to these incidents.

“This is the second time we have appealed for information.

READ MORE: Dogs poisoned DELIBERATELY while out walking in Glasgow park

“The first time biscuits were found was in March this year. 

“In total, this is the sixth incident of its kind we have had reported to us in the Anderston area in just over a year.

“There were reports of dogs ingesting poison in Alexandra Park in Glasgow just days after our first plea.

“This is a calculated and abominable criminal offence and we will do all we can to find the person responsible.

“It seems they won’t stop until an animal is hurt.

READ MORE: Deadly poison used to target dogs in Glasgow parks causes 'excruciating pain' and can kill in 30 seconds

“Someone knows something and we are desperate to put a stop to this.

“If anyone has any information on these incidences or sees anything suspicious, please report it immediately.”

In April a leading criminologist said the series of attempts to poison canines in Glasgow parks could be the work of a psychopath.

Professor David Wilson, the founding director of the Centre for Applied Criminology at Birmingham City University, said people who target pets may have a disorder called Zoosadism - meaning they take pleasure in making animals suffer.