I am a victim of this practice. The dirty deed involved two dodgy police officers, (1) DS Higham, and (2) DC Richardson, where suspect (1) made his own witness statement, and also made suspect (2's) witness statement, in the same matter, because (a) suspect (1) claimed both he and suspect (2's) had the same notes as each other, due to the fact that both had made up hand written notes together before going off duty, which entitled (b) suspect (2) to make out suspect (1's) witness statement in his absence - the problem is that because of a discrepancy (x) it turned out in court, that both officers did not have the same ñotes in their respective pocket books...
Not only did suspect (2) make suspect (1's) witness statement, in his absence which both signed, but as a result of a discrency (x), Suspect (2) caused two additional retyped pages to be added into the original 9 page witness statement (numbered pages 5 and 6), but suspect (2) discarded the original page 5 contents without suspect (1's) knowledge, and used typex to cross out original page numbers, 6, 7, 8 and 9, and retyped these by renumbering them in sequence, 6, 7, 8, 9 and 10. Thereby, turning the original 9 page witness statement (of suspect 1), into a 10 page witness statement...
Much later, after an independent police investigation, it transpires, that the notes in suspect (2's) pocket book was not recorded at the same time as suspect (1) recorded the alleged same notes in his (1) pocket book, because suspect (2's) pocket book, was not even issued to him for him to use, until 6 days after the occasion suspect (2) and suspect (1) allegedly made their notes up together in 6 days previously...
What these two bent coppers did to me by fabricating their evidence in this manner typifies why I have a huge distrust of the police, judges, and the criminal justice system in general. Criminals like these all piss in the same pot and look after one another. You scratch my back and I'll scratch yours...