TZ has for Colombia a single period with time zone 4h west.

# Rule NAME    FROM    TO      -       IN      ON      AT      SAVE    LETTER/S
Rule    CO      1992    only    -       May      3      0:00    1:00    -
Rule    CO      1993    only    -       Apr      4      0:00    0       -

I think the end date 4 April is wrong, it should be 6 February 24h or 7 February 0h

The time shift was called Hora Gaviria, and caused by shortage of electricity in connection with El Niño .

Source: DECRETO 267 DE 1993

https://www.suin-juriscol.gov.co/viewDocument.asp?ruta=Decretos/1061335

Artículo 1° Adoptar como hora legal en el territorio de la República, la del Tiempo Universal Coordinado, UTC, disminuido en cinco (5) horas.

Artículo 2° El cambio de hora se hará efectivo a las veinticuatro horas del día 6 de febrero del presente año.

There is also a newspaper article https://www.eltiempo.com/archivo/documento/MAM-32922
of 4 feb 1993, but the text is less clear to my limited understanding of Spanish.