diff --git a/ocat.c b/ocat.c
index 616a0d0..5a63d92 100644
--- a/ocat.c
+++ b/ocat.c
@@ -89,6 +89,7 @@ void usage(char *prog)
 	printf("           geojson\n");
 	printf("           raw\n");
 	printf("           tabular\n");
+	printf("  --killdata                   requires -u and -d\n");
 
 	exit(1);
 }
@@ -97,7 +98,7 @@ int main(int argc, char **argv)
 {
 	char *progname = *argv, *p;
 	int c;
-	int list = 0;
+	int list = 0, killdata = 0;
 	char *username = NULL, *device = NULL, *time_from = NULL, *time_to = NULL;
 	JsonNode *json, *obj, *locs;
 	time_t now, s_lo, s_hi;
@@ -131,11 +132,12 @@ int main(int argc, char **argv)
 			{ "from",	required_argument, 0, 	'F'},
 			{ "to",		required_argument, 0, 	'T'},
 			{ "format",	required_argument, 0, 	'f'},
+			{ "killdata",	no_argument, 0, 	'K'},
 		  	{0, 0, 0, 0}
 		  };
 		int optindex = 0;
 
-		c = getopt_long(argc, argv, "hlu:d:F:T:f:", long_options, &optindex);
+		c = getopt_long(argc, argv, "hlu:d:F:T:f:K", long_options, &optindex);
 		if (c == -1)
 			break;
 
@@ -171,6 +173,9 @@ int main(int argc, char **argv)
 					exit(2);
 				}
 				break;
+			case 'K':
+				killdata = 1;
+				break;
 			case 'h':
 			case '?':
 				/* getopt_long already printed message */
@@ -185,6 +190,22 @@ int main(int argc, char **argv)
 	argc -= (optind);
 	argv += (optind);
 
+	if (killdata) {
+		JsonNode *killed, *f;
+
+		if (!username || !device) {
+			fprintf(stderr, "%s: killdata requires username and device\n", progname);
+			return (-2);
+		}
+
+		fprintf(stderr, "Storage deleted these files:\n");
+		killed = kill_datastore(username, device);
+		json_foreach(f, killed) {
+			fprintf(stderr, "  %s\n", f->string_);
+		}
+		return (0);
+	}
+
 	if (!username && device) {
 		fprintf(stderr, "%s: device name without username doesn't make sense\n", progname);
 		return (-2);
@@ -233,8 +254,6 @@ int main(int argc, char **argv)
 	}
 
 
-	
-
 	/*
 	 * If any files were passed on the command line, we assume these are *.rec
 	 * and process those. Otherwise, we expect a `user' and `device' and process
diff --git a/storage.c b/storage.c
index 5841d04..7847d06 100644
--- a/storage.c
+++ b/storage.c
@@ -6,6 +6,7 @@
 #include <dirent.h>
 #include <errno.h>
 #include <fnmatch.h>
+#include <unistd.h>
 #include <ctype.h>
 #include "utstring.h"
 #include "config.h"
@@ -481,3 +482,66 @@ JsonNode *geo_json(JsonNode *location_array)
 
 	return (fcollection);
 }
+
+/*
+ * Remove all data for a user's device. Return a JSON array of deleted files.
+ */
+
+static int kill_datastore_filter(const struct dirent *d)
+{
+	return (*d->d_name == '.') ? 0 : 1;
+}
+
+JsonNode *kill_datastore(char *user, char *device)
+{
+	static UT_string *path = NULL, *fname = NULL;
+	JsonNode *killed = json_mkarray();
+	char *bp;
+	struct dirent **namelist;
+	int i, n;
+
+	utstring_renew(path);
+	utstring_renew(fname);
+
+	if (!user || !*user || !device || !*device)
+		return (killed);
+
+	for (bp = user; bp && *bp; bp++) {
+		if (isupper(*bp))
+			*bp = tolower(*bp);
+	}
+	for (bp = device; bp && *bp; bp++) {
+		if (isupper(*bp))
+			*bp = tolower(*bp);
+	}
+
+	utstring_printf(path, "%s/rec/%s/%s", STORAGEDIR, user, device);
+
+	if ((n = scandir(utstring_body(path), &namelist, kill_datastore_filter, NULL)) < 0) {
+		perror(utstring_body(path));
+                return (killed);
+	}
+
+	for (i = 0; i < n; i++) {
+		char *p;
+
+		utstring_clear(fname);
+		utstring_printf(fname, "%s/%s", utstring_body(path), namelist[i]->d_name);
+
+		p = utstring_body(fname);
+		if (remove(p) == 0) {
+			json_append_element(killed, json_mkstring(namelist[i]->d_name));
+		} else {
+			perror(p);
+		}
+
+		free(namelist[i]);
+	}
+	free(namelist);
+
+	if (rmdir(utstring_body(path)) != 0) {
+		perror(utstring_body(path));
+	}
+
+	return (killed);
+}
diff --git a/storage.h b/storage.h
index aba3c1c..41c93cd 100644
--- a/storage.h
+++ b/storage.h
@@ -9,5 +9,6 @@ JsonNode *lister(char *username, char *device, time_t s_lo, time_t s_hi);
 void locations(char *filename, JsonNode *obj, JsonNode *arr, time_t s_lo, time_t s_hi, int rawmode);
 int make_times(char *time_from, time_t *s_lo, char *time_to, time_t *s_to);
 JsonNode *geo_json(JsonNode *json);
+JsonNode *kill_datastore(char *username, char *device);
 
 #endif