A defence lawyer on Monday called for the dismissal of murder charges against a 14-year-old girl accused of killing her 35-year-old husband with rat poison in the country’s deeply conservative north.

“We urge your lordship to discharge and acquit the accused,” lawyer Hussaina Aliyu said at the High Court in Gezawa, a small town outside the state capital Kano.

Prosecutors say Wasila Tasi’u, who comes from a poor and deeply conservative Muslim family, poisoned the food served at a party last year after marrying Umar Sani in Kano state, in a case that has thrown a spotlight on child marriage.

Aliyu said the prosecution has failed to establish a link between the cause of Sani’s death and Tasi’u’s intent to kill the man, who was in his mid-thirties.

The lawyer also questioned the admissibility of a key witness of the prosecution — a seven-year-old girl identified as Hamziyya — who was living in Sani’s house when he died.

Hamziyya is the sister of Tasi’u’s “co-wife”, referring to a woman that the deceased farmer had married previously in a region where polygamy is widespread.

The young girl testified that Tasi’u gave her money to buy rat poison from a local shop, but the defence claimed the state had breached the law by calling a seven-year-old witness. 

Prosecutors seeking the death penalty say they have provided sufficient evidence to support their case.

The court is expected to decide whether it will dismiss the charge by March 31. 

Appearing in court wearing a full face veil or niqab for the first time, Tasi’u said nothing throughout Monday’s short hearing, which was attended by a handful of reporters.

Both Sani’s family and Tasi’u’s own parents have denied she was forced into marriage, claiming instead that 14 is a standard marrying age in northern Nigeriaand that she chose Sani from a range of suitors.

Rights activists, including in Nigeria’s mostly Christian south, have condemned the prosecution, arguing that Tasi’u should be treated as a victim entitled to treatment. 

Legal opinion on whether Tasi’u can be tried for murder as an adult is also divided, but a previous defence motion calling for her case to be referred to a juvenile court was rejected. 

According to Human Rights Watch, Nigeria is not known to have executed a juvenile offender since 1997, when the country was ruled by military dictator Sani Abacha.