Police chief has transferred the Sub-Inspector following the protests. (Representational)

A couple committed 'suicide' in their house near Changanassery in the district today after the husband, who worked in a jewellery shop, was allegedly tortured by police in connection with a gold theft case, police said.

The deaths triggered an agitation by workers of Congress and BJP in the area and the sub-inspector who was accused of custodial torture had been transferred, they said.

Sunil Kumar, 31, and Reshma, 27, had taken poison and died, the police said.

The couple's relatives alleged the two took the extreme step after Mr Kumar was accused of gold theft and tortured during interrogation, the police added.

Mr Kumar was summoned for interrogation based on a complaint from his employer, who is also a CPI(M) councillor, about the theft, they said.

The Congress-led United Democratic Front gave a call for a dawn-to-dusk hartal in protest against the incident.

The Kottayam District police chief has transferred the Sub-Inspector following the protests, police said.

The incident comes months after a youth, S R Sreejith, died after allegedly being tortured in police custody on April 9, over which the opposition had attacked Chief Minister Pinarayi Vijayan, holding charge of the Home portfolio.