David Micaelo Guzman, 21, was killed with a single bullet to the head shortly before dawn on August 2 as he slept in the home he had shared with his two siblings in the Torrejon de Ardoz suburb of Madrid.
His younger sister raised the alarm and told police she had seen two masked gunmen running from the property before speeding off in a dark BMW.
Initially police investigated whether the shooting had occurred during a disturbed burglary but there was no sign of a break-in and the intruders appeared to have been let in to the property from the inside.
On Thursday the sister, aged 16 and who has not been named by police, was remanded into custody at a youth detention centre, charged with planning the hit on her brother after he allegedly told her to break up with her boyfriend.
She is accused of persuading her boyfriend, who is named only as Miguel F.D, 22, and a friend of his named as Francisco Jose R M, 20, to carry out the murder.
Both men were remanded to prison by a judge on Thursday.
The victim had reportedly threatened violence if he discovered his sister and the 22-year-old, who had a record for drug trafficking, were still seeing each other after he ordered her to end the relationship.
The 16-year-old girl had lived alone with her two older siblings following the divorce of her parents five years ago.
| Posted: at | |
TRENDING GISTS 
Toyin Lawani Writes Open Letter To Asake Over New Hairstyle
VIDEO: Skitmaker, Erekere Shows Off His Newly Acquired Benz GLE
BREAKING: Vice President Shettima Cancels Summit Trip To US Over Faulty Aircraft
How British Charity Employed Nigerian Man, Peter Omoruyi Convicted For Sex Trafficking In France