The Past Tense

The past tense employs in Kareyku the following transitions for the positive:

Transition 1 is expressed by infix -kan
Transition 2 is expressed by infix -dan
Transition 3 is expressed by infix -tan

So pretty much the same as the present plus the suffix -n. Thus the same happens for the negative, which is:

Transition 1 is expressed by infix -ken
Transition 2 is expressed by infix -den
Transition 3 is expressed by infix -ten

Pretty simple. Note that the past tense ends in -n and so when using an evidential it will take the long version. This is the explanation why you have long and short evidentials, the long ones are mostly used when the past is used, because Kareku doesn't allow nasal + consonant codas. Thus:

tokikansi. I protected (it). With fact evidential.
qappakanni. I ate (it). With hear-say evidential.