After horrifying footage showing monkeys screaming in pain while strapped into metal harnesses leaked out, the German laboratory faces closures following a raid by authorities.

A family-owned company, Laboratory of Pharmacology and Toxicology (LPT), had been reported to conduct toxicity testing on animals for pharmaceutical, industrial, and agrochemical corporations.

These cruel practices impelled activist Soko Tierschutz and Cruelty-Free International to carry out an undercover investigation on LPT to unveil the harrowing animal abuse allegedly taking place at the facility.

The secret probe took place between December 2018 and March 2019. It involved an undercover worker securing a job at the lab after the Pharmacology and Toxicology lab put out an advert for new employees.

The undercover worker reported witnessing toxicity testing on animals, including cats, monkeys, beagles, and rabbits, supposedly carried out for industries and companies in Germany and worldwide. The activist found that the animals were kept in horrifying conditions.

Using a secret camera, the activists filmed footage showing macaques bound in brackets in rows, on the wall, and their heads locked in restrains.

Other shocking images revealed a beagle bleeding profusely in a cramped cage. Other animals had pipes inserted into their throats and were forced to take capsules before being left in cells to suffer and bleed after experiments.

Friedrich Mülln, from Soko Tierschutz, explained:

"The animals were even still waggling their tails when they were being taken to be killed. The dogs were desperate for human contact."

"The worst treatment was kept for the monkeys. The macaque's bread of monkeys is small, relatively light primates, which are often used for animal experiments at LPT."

"They are kept in cramped conditions in small cages. Many of the animals have developed compulsive tendencies and are seen going round in circles."

Friedrich added that cats were reportedly given up to 13 injections every day by untrained assistants and treated with violence by workers in the facility.

Michelle Thew, Chief Executive of Cruelty Free International, said:

"Our investigation has uncovered appalling animal suffering, inadequate care, poor practices, and breaches of European and German law."

"We are calling for the Laboratory of Pharmacology and Toxicology (LPT) to be closed. We are also calling for a comprehensive review of the use of animals in regulatory toxicity testing in Europe, including the UK."

"Every investigation, without fail, shows a similar tale of misery and disregard of the law."

According to Cruelty-Free International, toxicity testing involves poisoning animals to see how much of a chemical or drug it takes to cause severe harm in an attempt to measure what a 'safe' dose for humans might be.

Animals are also made to eat, inhale, or are injected with increasing amounts of chemical substances to determine the toxic effects, which can be severe.

The effects of toxicity testing on animals include "vomiting, internal bleeding, respiratory distress, fever, weight loss, lethargy, skin problems, organ failure, and even death," and no anesthetics or pain relief are provided.

The video of this horrifying animal cruelty incited anger after the activists shared the footage on social media. Police are investigating the case.