Husband was having affair with 17-year-old girl before he killed himself and family

A father gassed his entire family to death after his wife discovered his affair with a 17-year-old girl in the Philippines and demanded a divorce, an inquest has heard.

Maria Lutz, 43, Fernando Manrique, 44, and their children Elisa, 11, and Martin, 10, were found dead, along with the family dog, in their Sydney home in October 2016.

Mr Manrique is believed to have set up an elaborate system of pipes in the ceiling to spray odourless carbon monoxide gas throughout the house.

Counsel assisting the Coroner Adam Casselden told the inquest on Monday that the businessman was seeing the teenager for four months before the deaths.

The girl named Jamilyn told Australian police they met in a bar she worked in and after two weeks together he told her to quit her job.

She said Mr Manrique promised to support her and buy her a house, but never actually followed through on that plan.

When Ms Lutz discovered the affair she demanded a divorce from the already-unhappy marriage.

Police forced their way in to the house in Davidson, on Sydney’s northern beaches, on October 17, 2016, after the family didn’t turn up to work and school

Mr Manrique’s body was in the living room, Ms Lutz and Elisa next to each other in a bedroom, and Martin in a third room beside their bull mastiff Tequila

Police forced their way in to the house in Davidson, on Sydney’s northern beaches, on October 17, 2016, after the family didn’t turn up to work and school.

Mr Manrique’s body was in the living room, Ms Lutz and Elisa next to each other in a bedroom, and Martin in a third room beside their bull mastiff Tequila.

Mr Casselden told the inquest the alleged killer owed the Australian Tax Office more than $15,000 and was in other financial difficulty.

More to come