The attacker who shot dead six people at a Nashville school had been planning the massacre for months, police have said.

Journals found in Audrey Hale’s car and bedroom outlined plans to “commit mass murder at The Covenant School”, the Metropolitan Nashville Police Department said.

Three adults and three nine-year-old students were killed in the shooting at the private Christian school on 27 March.

Police said Hale “considered the actions of other mass murderers” but are yet to establish a motive.

The writings remain “under careful review”, the police department said.

Hale – a former student at the school – shot a total of 152 rounds during the incident, including 126 rifle rounds and 26 nine-millimetre rounds, before being killed by police.

The three children who were killed in the shooting were Evelyn Dieckhaus, Hallie Scruggs and William Kinney.

The head of the school, Katherine Koonce, 60, Mike Hill, 61, and 61-year-old substitute teacher Cynthia Peak were also killed.

On Monday, students across Nashville walked out of class to protest gun violence at the Tennessee Capitol. Parents and children previously took to the Capitol on 30 March, holding signs such as “Attending school should not be a death sentence”.

Bill Lee, the governor of Tennessee, also unveiled proposals to allocate enough funding to place a school resource officer in every public school, as well as increase security in school buildings and boost mental health resources.

His announcement on Monday marked the first public address the governor has made since the shooting.

Read more:
TV star helped children fleeing Nashville shooting
Video shows moment attacker was shot dead
What we know about killer Audrey Hale

Police said Hale was under a doctor’s care for an undisclosed “emotional disorder” but have not said there is a link between the medical care and the shooting.

In the build-up to the shooting, Averianna Patton, a former basketball teammate of Hale said the 28-year-old sent her Instagram messages in which they talked about not wanting to live anymore and said that their family did not know what they were about to do.

Ms Patton said she saw the messages at 9.57am (3.57pm UK time) on Monday, less than 20 minutes before police said they were told about an attack at the Covenant School.

In their last message, Hale said that something bad was about to happen and asked for forgiveness.

Social media accounts and other sources indicate that Hale identified as a transgender man.