A German man accused of killing his wife and 10-year-old son in a cave in Tenerife has gone on trial after his other, seven-year-old son managed to flee and raise the alarm.

The defendant claims that he was acting under the influence of drugs that had addled his mind.

The gruesome murders took place in a cave near Adeje, which is a town and municipality in south-western Tenerife, in the Canary Islands, in Spain, on 23rd April 2019.

The trial over the two murders and one attempted murder began on Monday, 24th January, in Santa Cruz de Tenerife, the capital of the island of Tenerife and of the Canary Islands.

German citizen Thomas Handrick, 44 at the time of the incident, stands accused of murdering his wife Silvia and one of his sons, Jacob, 10, in the Adeje cave.

His other son, 7, survived the ordeal by fleeing. He wandered around for hours before bumping into a Dutch woman.

The prosecutor’s office is reportedly requesting that the defendant be jailed permanently, with the sentence reviewable periodically.

It is alleged that the defendant took his wife and children to the cave on an excursion, but once they arrived there, he allegedly began violent beating his wife and his eldest son.

The couple were reportedly in the process of separating. Handrick was reportedly familiar with the area, having spent long periods of time there.

The youngest son, named as Jonas, upon realising that he was potentially in danger, ran away down the mountain and wandered around for hours before bumping into the Dutch woman, whom he reportedly asked for help.

With the help of the Dutch woman, unnamed, who acted as a translator for him, the young boy told the police about the horrific incident he had seen.

It is alleged that the defendant hatched a plan to “end the life of his partner”, who was allegedly reluctant to divorce, which consisted of taking his family on a 10-kilometre (6.2-mile) hike to the cave from the family home, with the lure of gifts that he had supposedly hidden in the cave.

It is also alleged that he chose the place on purpose because it was “solitary and secluded” and would enable him “to ensure the execution of his acts and avoid defence by third parties of his family”.

Handrick is said to have spent considerable amounts of time on the island of Tenerife during the winter months and he also reportedly took medication for pain and depression, including morphine.

Handrick allegedly attacked his wife outside the cave with a rock and crushed her skull.

He claimed on Monday that his actions were in part caused by his brain being addled by the drugs. He also claimed that it was his wife who had attacked him and that he had been acting “in a panic” and in self-defence.

The 10-year-old son is said to have tried to defend his mother, but he was also allegedly beaten to death by his father.

The seven-year-old son managed to flee and came across the Dutch citizen after travelling more than four kilometres (2.5 miles) on a narrow path.

The defendant is believed to have left him to his fate, thinking that he would not survive alone in the wild.

The defendant is then said to have gone home and washed before resting. The police arrived at around 7pm and arrested him.

The defence has argued that the defendant was not of sound mind and that his wife wanted to divorce him. His lawyer, Alberto Suarez Bruno, said: “He is a very tormented person who has suffered a lot.”

He added that the defendant is “also a victim”. It is currently unclear if a psychological evaluation of the defendant has been scheduled.

The defence argues that Handrick did not throw the stones at his wife, but simply “returned” them to where they had come from after they were thrown at him.

After his youngest son fled, he said that he went to look for him, and when he returned to the cave, his wife and eldest child were no longer in front of it but had gone inside it.

He claims that his mind was addled by the morphine, saying that it appeared to him at the time that his wife was emitting “roars” and her face, which was “half-missing”, was “full of light” and her eyes with “a greenish glow”, despite the darkness that reigned in the cave, “like on a ghost train”.

The defendant said that he threw one last stone before collapsing.

He said that when he left the cave he saw that Jonas had left the area and he walked “from here to there” to see if he could find him, but he was “disoriented”, as if he were the spectator of “a movie”, in spite of which he was able to return home, undress, clean up, and throw his bloodstained clothes into a nearby bin.

The trial is set to take place over the course of the next week and it is believed that it will last until Thursday, 3rd February.

Thomas Hendrick stands charged with two counts of murder and with one count of attempted murder.