Bangalore: A Kerala court on Thursday sentenced to death a migrant labourer for the 2016 rape and murder of a law student.

The principal sessions court in Ernakulam ruled that it was a "rarest of the rare" case and handed the maximum punishment to Ameerul Islam, 25, who hails from Nagaon in Assam and had been working in Kerala for the past eight years. The court had held him guilty on Tuesday.

Ameerul had trespassed into the house of the 30-year-old law student on April 28, 2016, in Perumbavoor and raped and murdered her by stabbing her at least 30 times, disembowelling her and mutilating her genitals.

The brutality of the crime had shocked the state and put the Congress-led government under tremendous pressure over women's safety issues before the Assembly elections.

The Ernakulam court compared the crime to the 2012 Delhi gang rape and murder.

Other than the death sentence under IPC Section 302, the court handed a life term and another 18 years in jail to Ameerul for proven charges of rape, death due to rape and trespassing.

Defence counsel B.A. Aloor told reporters he would file an appeal before Kerala High Court. "It is his right to appeal in the high court, where we will raise our concerns about the inadequacies of the investigation," the lawyer said.

When the court gave time to Ameerul to make his statements through an interpreter on Wednesday, he kept pleading innocence.

Aloor, a top criminal lawyer who takes up controversial cases, had also pleaded against punishing an "innocent man" and argued that there was evidence of Ameerul being implicated.

Kerala director-general of police Loknath Behera lauded his officers who cracked the case and said the verdict was the outcome of a "systematic" investigation. "We built the case step by step with evidence based on forensic science," he said.

The crime had taken place weeks before the Kerala Assembly elections and triggered protests by all sections of the society.

The Congress-led United Democratic Front government lost the May elections and its successor, the CPM-helmed Left Democratic Front, ordered a fresh probe under additional director-general of police B. Sandhya.

A special police team tracked Ameerul down to Kancheepuram in Tamil Nadu and arrested him on June 16 last year. The manhunt had led policemen to 10 states, including Bengal.

The trial began on April 14 this year and continued for 85 years. The prosecution presented more than 100 witnesses, 290 documents and 36 pieces of material evidence, including the weapon used.