Dr Virginia Fitzpatrick-Swallow, a consultant forensic pathologist, was giving her evidence on the fourth day of the trial and she told the court she was confident that "a woman of this age and this health status" could not have drown accidently. She said the post-mortem results suggested Ms Aldrich had been held in the water by someone else. Previously, the court has heard how Robert McWhir, 26, of Potton Road, St Neots, had been seen holding Ms Aldrich's body under shallow water in an area of scrubland at Love's Farm, St Neots. McWhir denies murdering Ms Aldrich at 2.30am on December 22 last year. Ms Aldrich was found face-up in a drainage pond and by the time she was discovered she was in cardiac arrest and had stopped breathing. Attempts were made to revive her at the scene and she was taken to Hinchingbrooke Hospital where she was pronounced dead at 3.54am. Dr Fitzpatrick-Swallow told the court the post-mortem, which had taken place at Addenbrooke's Hospital on the afternoon of December 22, showed Ms Aldrich had 31 external injuries, including bruises to the side of the head, front of the face and arms. She said there was a lot of "frothy fluid" in the airways and the lungs, including the plural space, which is a relevant finding usually associated with asphyxiated deaths, such as drowning. She also told the court how the lungs were "heavy and prominent" as they had become "over inflated by fluid" which is also a feature consistent with drowning. Ms Aldrich also had a lot of plant life and vegetation in her hair as well as silt. Dr Fitzpatrick-Swallow also explained to the court that Ms Aldrich had silt in-between her teeth, which suggests she was held face down in the water. The court then heard how Ms Aldrich did not have any natural disease and her stomach was lined with fine silted material. She went on to explain there was bruising to both sides of her face, which she believed had been caused by "blunt force trauma", which usually occurs when people are being held with force, or during a physical fight. Dr Fitzpatrick-Swallow also told the court how Ms Aldrich had fractured ribs, but concluded this was due to cardiopulmonary resuscitation at the scene. She said: "In addition to this, there were injuries to the back and underneath the shoulder blades. This would be in keeping with the fact that there was pressing down hard on her, as it has taken some significant pressing to create these injuries." Dr Fitzpatrick-Swallow told the court that she couldn't be sure if someone was kneeling on Ms Aldrich but she believed that Ms Aldrich had been held down by force. She also told the court how there was bruising to the front, right and left side of Ms Aldrich's face which showed that she was struggling and moving her head from side to side, trying to get air. Dr Fitzpatrick-Swallow also said that the face had been pressing down on something in the pond, and suggested that it could have been the bottom of the pond due to the shallow water. David Whittaker, for the defence, asked Dr Fitzpatrick-Swallow if Ms Aldrich could have slipped into the water and fallen unconscious. He also suggested the bruising had occurred as she was being pulled out of the water. She told Mr Whittaker: "The victim would have had to have circulation and a beating heart for her to obtain bruises like this, I do not accept that. There is a clear indication that there has been a struggle." She concluded: "I am satisfied that the cause of death is drowning. The bruises suggest that she was struggling, as well as the silt that was found internally. These to me are injuries that are consistent with a struggle. Her nose and mouth was covered by water which is why I have said that the cause of death is drowning. If she was dragged out it wouldn't cause the bruising to her face. There is nothing that a woman of this age and this health status that would suggest that she accidently drowned. I believe her head was forced beneath the water." This afternoon (Thursday) the court also heard from Lindsay Ward, a forensic toxicologist. Ms Ward told the court there were traces of alcohol, cocaine and cannabis in Ms Aldrich's system. However, Ms Aldrich had 40mg per 100ml of alcohol in her blood, which is half the legal driving limit. Ms Ward said: " She would not have been intoxicated." She also explained to the court that she couldn't comment on the effect that the mixture of drugs could have had on Ms Adlrich, as people's bodies react differently. She said: "It is very difficult to predict the outcome of the substance interaction." Ms Ward also gave evidence relating to McWhir's blood samples, and said that it was "possible that he could have been significantly intoxicated at the time of the incident" but she was unable to say for sure, due to the fact that the samples had being taken 11 hours after the incident. The case continues.