When Peter Mutuku Mutisya’s body was found floating in a dam on Del Monte’s farm in Kenya last month his family and friends had already been searching for days. Mutisya, 25, worked as a chemical sprayer at the neighbouring farm and was relied on by his relatives, to whom he would offer lifts on his prized motorbike. His mother, Hannah Wanjiru Nyambura, a deacon in the church, liked to joke that he needed to get married and name his first child after her. Her faith meant that when she heard that her son had last been seen chased by guards after stealing pineapples from Del Monte, she started praying. Martin Chege Mutuku, 27, said he rowed with Mutisya and another friend across a dam into the farm on rafts on Monday 13 November to take ripe pineapples from Del Monte, the world’s biggest supplier. In field 74, they found plump fruit that was easy to pick and quickly got to work. Mutuku said they were leaving the field and Mutisya had gone on ahead to grab their sacks when security guards appeared. “I saw three guards approach from the corner where the winding path Peter used curves at,” Mutuku said. “One shouted: ‘Shikeni hiyo mbwa!’ [‘Catch that dog!’]. I dropped my pineapples but before I could go far, one had caught up with me, wrestled me on to the ground and the other one joined as they started beating me.” The third friend, who did not want to be identified, told the Guardian he made it away from the scene when the guards appeared. Mutuku said that while he was held on the ground with his arms and legs bound, the guards heard Mutisya returning with sacks and chased after him. “I heard a scream and then silence a few minutes after the two guards left me.” It was another four days before villagers searching the dam found Mutisya’s body. His father, Samuel Katendie, went to identify the body in the back of a truck and was shocked by what he found. His son’s body was swollen from being in the water, and he said: “He was bleeding at the back of his head. His neck had marks like he [had been] strangled.” The case has been likened to that of Saidi Ngotho Ndungu, whose body was discovered in Dam 7 on the Del Monte plantation in May 2013 two days after he was pursued by Del Monte guards. Two friends said they were with Ndungu and were caught trespassing on the farm. A witness statement given to police two days after Ndungu’s body was found claimed guards beat him with wooden clubs and that he was heard pleading with them not to kill him. His death certificate gave drowning as the cause. When these and other allegations were put to Del Monte in June they said they were taking them extremely seriously and were subject to a “full and urgent investigation”. Postmortems are typically conducted by public doctors but Mutisya’s was different. In the examination room alongside the government doctor was a private pathologist who ran his own hospital business. He told the Guardian he charged Del Monte for his services. Mutisya’s mother, Hannah, 41, said: “When I heard there was a Del Monte representative in the morgue, I lost hope.” When the doctors finished, the family were told their verdict: death by drowning. Mutisya’s father, Samuel, said: “As a parent, I lost hope for justice after the doctor said there was no injury. I did not even eat that night.” The official postmortem and the report written by the pathologist for Del Monte seen by the Guardian both give the cause of death as drowning with no injuries recorded. The report for Del Monte is the most emphatic, writing: “NO evidence of involvement of person (third party) into the death of this person since there were no injuries seen during postmortem examination.” The Guardian shared both reports and a photograph of the body with a leading British forensic pathologist, who did not want his name published. The UK pathologist said he believed he could see marks on the body in the photograph that could be injuries. He noted darker areas on the forehead and cheek as well as parallel lines visible on the right arm, which he said could be marks from a ligature or tram lines consistent with being beaten with, for example, a baton. The British pathologist said it was possible there were injuries not visible in the photograph because of areas (including the neck and wrists) in shadow and the lack of a back view. Decomposition can also mask injuries. It is common for bodies left in water to be damaged after death. But the British pathologist said missing details in the postmortem reports rang “lots of alarm bells” and that as a “bare minimum” you would expect the marks to be recorded, whether or not they were assessed as injuries. He said neither report conformed to acceptable forensic standards. He also identified contradictory findings and omissions that he said raised questions about whether the reports had been written to support the idea Mutisya had drowned. He and another British pathologist who analysed the reports noted that only the police-commissioned report recorded petechial haemorrhages, pinprick bleeding around the eyes. This can be indicative of strangulation, though can have other causes, including drowning. They said that at the very least they should have prompted a written note on an internal and external examination of the neck but this is not given in either report. The Kenyan pathologist commissioned by Del Monte insisted he had drawn the right conclusions. He said: “Yes, My report is very emphatic. This is the standard practice in forensic postmortem.” He questioned whether any pathologist could “make any meaningful comment” from a photograph of a decomposed body. Mutisya was buried on 28 November by his family before they had a written copy of the postmortem. Human rights observers are concerned the report was withheld from them until after the body was buried, when they would not be able to request an independent medical assessment without exhumation. His mother said of the postmortem findings: “I did not agree with the result because Chege who was with him said he heard Peter scream. I don’t believe what they said that he drowned.” A spokesperson for Del Monte said: “Del Monte Kenya fully cooperated with Kenyan authorities throughout its investigation last month. According to the postmortem report that was approved by the Directorate of Criminal Investigations Officer and four different doctors – all of whom were present during the postmortem – the individual died by drowning, and there were no indications of foul play. “Our heartfelt condolences go out to the bereaved family and friends during this difficult time. We believe in the Kenyan judicial system.” It said questions about the Kenyan judicial system should be directed to “Kenyan authorities who are taking the lead on this investigation.” The police did not respond to the Guardian’s requests for comment.