Prefectural police in Gunma have arrested four Vietnamese men living in the town of Ota on suspicion of slaughtering a pig in their apartment.

According to the Mainichi Shimbun, the men were arrested on Oct. 28th and charged with violating the Slaughterhouse Act, which prohibits the slaughter of livestock in unauthorized locations. Prefectural police did not disclose whether the four men had admitted to the allegations.

Police told reporters that a search of the men's apartment found bristles believed to belong to at least one pig, and a luminol reaction test indicated traces of blood, leading investigators to suspect that the pig had indeed been butchered in the apartment.

Two of the four men arrested are aged 32, while the other two are 22 and 27 years old. The men are all technical interns. They are accused of teaming up to slaughter a pig in July in a property not authorized as a slaughterhouse by the prefectural government.

Prefectural police are poised to question the men over how they obtained the pig. They suspect that they are one of several Vietnamese groups involved in the spate of thefts of livestock and fruit from farms north of Tokyo.

Police were alerted to the alleged crime after images of a pig, apparently being slaughtered in the kitchen of the 27-year-old's apartment, were posted on social media. They subsequently searched his home and confiscated 38 pork chops and five kitchen knives.

A 49-year-old woman living near the man’s apartment told the Mainichi Shimbun that she had “been smelling a strangely sour, animal-like odour for the past month or two.”

The 27-year-old has been in trouble with local police on another occasion. On Oct. 4th, he was arrested by local police at a farm near Ota on suspicion of stealing a gourd.

The arrests came just two days after prefectural police apprehended 13 Vietnamese men and women living in an apartment complex in Ota on suspicion of overstaying their visas.

The arrests were made following a probe into a vehicle found to be carrying meat and fruit to a delivery centre in the town. Police have confirmed that the same vehicle was seen travelling around farming districts in Saitama prefecture, which was hit by a string of thefts in August.

Investigators seized delivery slips bearing the names of two of the 13 Vietnamese, which police say shows that they had sent meat and other products to compatriots living in Japan. The group is suspected of selling the products after posting messages on social media.

Police are looking into their possible involvement in other thefts in the region. Gunma prefecture has been reeling from a spate of thefts of livestock and fruit in recent months. Approximately 720 pigs, 140 chickens and 9,000 items of fruit, including pears and grapes, have been stolen from farms in the prefecture this year.

Farmers in neighbouring Saitama and Tochigi prefectures have also reported a string of thefts of pigs, calves and other farm produce.

Police are still trying to ascertain whether the four men arrested on Oct. 28th had contact with the 13 Vietnamese taken into custody two days earlier.