“It was I that/who + past tense” Vs. “It is I who/that + past tense?

[High on grammar]

Dear English teachers:
What is the difference between “It was I that/who + past tense” Vs. “It is I who/that + past tense?
Examples and their sources:
“I must tell you that it is I who went to the kitchen with my mother when Bernard met Kang,”

LIAISON

And it is I who wentto tell the people that the child had been murdered by his father.'

Tears of the Dead: The Social Biography of an African Family - Page 89

"It was I who did all these things . . .The Anointed, The Elect, and The Damned! - Page 138
It was I that wrote you the letters.

when should use a past tense after " I is I who/that...?
Thanks

[5jj]

What is the difference between “It was I that/who + past tense” Vs. “It is I who/that + past tense?

I may be missing something here, but I can't see any difference between those to, except that you have reversed the order of 'that' and 'who'.

wWhen should I/we/you/one use a past tense after " I is I who/that...?

When what 'I' did took place in the past.

[High on grammar]

I may be missing something here, but I can't see any difference between those two, except that you have reversed the order of 'that' and 'who'.When what 'I' did took place in the past.

If the action happened in the past , then why the sentence reads: It is (present tense) I that did it >

When do we say it IS I that did it and when " It WAS I that did it"?

Thanks

[5jj]

Sorry - I did indeed miss something.

'It was I ...' places the whole situation in the past.

'It is I ... 'draws attention to the fact that the speaker, who is (?: was) the person who did whatever it was identifies his/her present views/actions with those that happened in the past.

[High on grammar]

Thanks. But I would really appreciate it if you would explain it in a much simpler way so that I could understand what you mean by " identifies his/her present views/actions with those that happened in the past.

Thanks again