In the report opener below, is it correct to use '... obtained an oral and a written confession ...'? Or can I write '... obtained an oral and written statement ...'? It seems as though I need both 'an' and 'a' because we can say 'an oral' but not 'an written'. Also, because I obtained a confession from the interviewee by word of mouth, it was an 'oral' (not 'verbal') confession, correct?
On January 4th, 2013, at 8.05pm, I interviewed and obtained an oral and a written statement from John Doe, cashier, in which he admitted to stealing $100 cash from register no. 4.