WARSAW — The Polish owner of the truck used in the Berlin Christmas market massacre said the man found dead in the passenger seat was his employee and cousin, describing him as a “good guy” who appeared to have been stabbed and shot.

The 37-year-old Pole named Lukasz, who was shot dead according to German officials, was a driver for his cousin Ariel Zurawski’s transport company in northern Poland.

“One person would not have been able to overpower him,” said Mr Zurawski on Tuesday of the relative he had grown up with, a heavyset man who weighed 120kg and stood 183cm tall. “We could see injuries. His face was bloodied and swollen,” Mr Zurawski told private news channel TVN 24, referring to a photo he received from Polish police. “There was a stab wound. Police also told me there was a gunshot wound,” he said, adding that it was distressing to see the picture.

Mr Zurawski said the family — including his widow and 17-year-old son — was in shock, and Lukasz’s father was taken to hospital by ambulance when he got the news.

Mr Zurawski repeatedly spoke of the unfortunate set of circumstances that led to Lukasz’s death in Germany’s deadliest attack of recent years.

Twelve people were killed and almost 50 wounded when the lorry tore through the Berlin crowd on Monday, smashing wooden stalls and crushing victims.

Lukasz had been on the road for more than a week when he arrived in Berlin with a truck full of steel beams from Italy, according to Mr Zurawski.

He would normally have unloaded the steel immediately on Monday, but the receiving company asked to postpone the delivery until the following morning.

Lukasz parked in front of their warehouse in a neighbourhood with many Muslim residents, according to Mr Zurawski, who also said his cousin ate a kebab in a local restaurant and took a smiling selfie in the area.

“He absolutely wanted to return today, at the latest, to buy his wife a gift,” said Mr Zurawski.

Lukasz last spoke to his wife on the phone about 3pm local time, but it was a short conversation because she was still at work. They agreed to talk again an hour later, but at 4pm he was no longer answering.

Mr Zurawski said it later became apparent from the truck’s GPS system that the vehicle was switched on about 3.45pm, but only moved back and forth “as if someone was learning how to drive it”.

That, said Mr Zurawski, was when he knew something bad had happened, because Lukasz always scrupulously followed guidelines and would never have started the vehicle during a mandatory break from driving.

“At work, we called him ‘Inspector’ because he was so rigorous. He was a good guy,” he said.

The truck was fitted with automatic transmission and was easy to drive. It left its parking space about 7.40pm, driving the 10km or so to the Christmas market.

“Perhaps someone was guiding the driver because it’s not easy to cover that trajectory in Berlin (without getting lost),” said Mr Zurawski.

Polish prosecutors have launched an investigation into the killing, which has left the country’s trucker community reeling.

“We’re all in shock,” said Ms Anna Wrona, spokeswoman for their International Road Carriers Association, which has launched a donation drive for the victim’s family. AFP