What is the syntax for DELETE in OQGRAPH?

I am trying out OQGRAPH and one of the things I need to be able to do is DELETE an edge that is no longer valid. I could not find an example of the syntax of DELETE but the obvious syntax didn't seem to work. Here is what I did.

mysql> CREATE TABLE graph (
latch SMALLINT UNSIGNED NULL,
origid BIGINT UNSIGNED NULL,
destid BIGINT UNSIGNED NULL,
weight DOUBLE NULL,
seq BIGINT UNSIGNED NULL,
linkid BIGINT UNSIGNED NULL,
KEY (latch, origid, destid) USING HASH,
KEY (latch, destid, origid) USING HASH
) ENGINE=OQGRAPH;

mysql> INSERT INTO graph (origid,destid) VALUES
(1,2),(2,1),
(1,3),(3,1),
(3,4),(4,3),
(3,5),(5,3),
(5,6),(6,5);

Then I tried to delete one of the edges using the origid and destid and I get the following error message:

mysql> DELETE FROM graph WHERE origid=1 AND destid=2;
ERROR 1032 (HY000): Can't find record in 'graph'

Is there some other syntax that I should be using for DELETE?