A Spanish court has sentenced the head of an animal shelter to three years and nine months in jail for killing hundreds of healthy dogs and cats in a way that provoked “prolonged agony”, informs The Guardian.

The court in the southern city of Málaga also fined Carmen Marín Aguilar, 72, €19,800 after finding her guilty of animal cruelty and the falsification of documents.

Felipe Barco Gómez, 55, a caretaker at the Parque Animal shelter in Torremolinos on the Costa del Sol, was jailed for a year and ordered to pay a fine of €3,600 for his role in the deaths.

The court said Aguilar injected healthy animals of different breeds, mainly dogs and cats, with euthanizing drugs without sedation while Gómez held them down.

Aguilar used a smaller dose of the euthanizing drug than is advised in order to save money and injected it directly into muscle tissue instead of intravenously as recommended, it added.

This caused a “slow death with a painful and prolonged agony”, the court said in its ruling.

Prosecutors accused the pair of having killed 2,183 animals between January 2009 and October 2010, when the alleged slaughter came to light during an inspection of the facilities.

They believe the pair killed the animals to reduce costs and make room for the centre’s for-profit activities.

Prosecutors said the pair disconnected security cameras when they killed the animals and would play music over a megaphone to mask the ensuing howls.

Aguilar and Gómez denied killing the animals.