An 18-year-old man has been arrested on suspicion of murdering prominent plastic surgeon Alexander Aslani inside his Marbella clinic.
The Policia Nacional confirmed the arrest on Thursday evening as the investigation into the execution-style killing continued under judicial secrecy.
Officers have ruled out a link to organised crime but have not yet established or disclosed a confirmed motive.
One line of inquiry is whether the murder could be connected to somebody unhappy with the outcome of an aesthetic procedure.
However, investigators have stressed that this possibility remains unconfirmed.
Aslani, 57, was shot several times in the head inside Cirumed Clinic shortly before 6pm on Wednesday.
Initial witness accounts described a masked attacker arriving on a motorbike before entering the premises dressed in black, wearing a helmet, hood and face covering.
Up to three shots were reportedly heard before the gunman fled, possibly with the assistance of a second person.

Police initially suspected that a hired killer may have carried out the attack.
The alleged shooter has now been detained, although officers have not disclosed where or when the arrest took place.
The investigation remains open and further arrests have not been ruled out.
Aslani had more than 30 years of medical experience and carried out over 14,000 operations during his career.
He ran Cirumed Clinic alongside his wife and was named Spain’s best plastic surgeon in 2016, according to the centre’s website.
Between 2008 and 2018, he headed the plastic surgery departments at the Quiron hospitals in Malaga and Marbella.
He later founded Cirumed, where he specialised in advanced body-contouring treatments and developed the “Supercharged BBL”, a pioneering buttock augmentation technique combining fat transfer with implants.

The Malaga Medical Association issued a statement condemning Aslani’s killing in the ‘strongest’ terms.
It offered its condolences to his family, friends and colleagues and expressed concern over an incident of ‘extreme gravity’ in which a doctor was killed while carrying out his professional work.
The association said it had full confidence in Spain’s security forces and judicial authorities to clarify what happened and bring everyone responsible to justice.
