Jerome makes a self admission to tampering with Origen's writings.

He also makes clear that others followed his example and had omitted or added to "...EXPANDED ORIGEN..." 

Something he takes Rufinus of Aquileia to task over later, who retorts in his defense he was only following Jeromes example.

Here's the passage Rufinus quotes as proof and an excuse for his own tampering:

Latin text to be added when available:

JEROME (circa. 347-420 C.E.): “...Origen [2.] is a heretic, true; but what does that take from me who do not deny that on very many points he is heretical? He has erred concerning the resurrection of the body, he has erred concerning the condition of souls, he has erred by supposing it possible that the devil may repent, and— AN ERROR MORE IMPORTANT THAN THESE— HE HAS DECLARED IN HIS COMMENTARY UPON ISAIAH THAT THE SERAPHIM MENTIONED BY THE PROPHET{*} ARE THE DIVINE SON AND THE HOLY GHOST. If I did not allow that he has erred or if I did not daily anathematize his errors I should be partaker of his fault. For while we receive what is good in his writings we must on no account bind ourselves to accept also what is evil. Still in many passages he has interpreted the scriptures well, has explained obscure places in the prophets, and has brought to light very great mysteries, both in the old and in the new testament. IF THEN I HAVE TAKEN OVER WHAT IS GOOD IN HIM - AND - ( HAVE EITHER CUT AWAY ) - OR - ( ALTERED ) - OR - ( IGNORED WHAT IS EVIL ), AM I TO BE REGARDED AS GUILTY ON THE SCORE THAT - ( THROUGH MY AGENCY ) - THOSE WHO READ LATIN RECEIVE THE GOOD IN HIS WRITINGS - ( WITHOUT KNOWING ANYTHING OF THE BAD? ) IF THIS BE A CRIME - ( THE CONFESSOR HILARY ) - MUST BE CONVICTED; FOR HE HAS RENDERED FROM GREEK INTO LATIN ORIGEN'S EXPLANATION OF THE PSALMS AND HIS HOMILIES ON JOB. ( EUSEBIUS OF VERCELLÆ; ) WHO WITNESSED A LIKE CONFESSION, MUST - ( ALSO BE HELD IN FAULT; ) - FOR HE HAS TRANSLATED INTO OUR TONGUE THE COMMENTARIES UPON ALL THE PSALMS OF HIS HERETICAL NAMESAKE, - ( OMITTING HOWEVER THE UNSOUND PORTIONS ) - AND RENDERING ONLY THOSE PARTS WHICH ARE PROFITABLE. I SAY NOTHING OF - ( VICTORINUS OF PETAVIUM ) - AND - ( OTHERS ) - WHO HAVE MERELY FOLLOWED AND - ( EXPANDED ) - ORIGEN IN THEIR EXPLANATION OF THE SCRIPTURES...” - (Paragraph 2, Epistle 61, “To Vigilantius,” Letters of St. Jerome. Translated by W.H. Fremantle, G. Lewis and W.G. Martley. From Nicene and Post-Nicene Fathers, Second Series, Vol. 6. Edited by Philip Schaff and Henry Wace. (Buffalo, NY: Christian Literature Publishing Co., 1893.)
[FOOTNOTE *]: Isa. vi. 2. See Letter XVIII.
[FOOTNOTE]: Jeromes full name: Eusebius Sophronius Hieronymus